Provided by: tcsh_6.20.00-7build1_amd64 bug

NAME

       tcsh - C shell with file name completion and command line editing

SYNOPSIS

       tcsh [-bcdefFimnqstvVxX] [-Dname[=value]] [arg ...]
       tcsh -l

DESCRIPTION

       tcsh  is  an  enhanced  but  completely  compatible  version of the Berkeley UNIX C shell,
       csh(1).  It is a command language interpreter usable both as an  interactive  login  shell
       and a shell script command processor.  It includes a command-line editor (see The command-
       line  editor),  programmable  word  completion  (see  Completion  and  listing),  spelling
       correction  (see Spelling correction), a history mechanism (see History substitution), job
       control (see Jobs) and  a  C-like  syntax.   The  NEW  FEATURES  section  describes  major
       enhancements  of  tcsh over csh(1).  Throughout this manual, features of tcsh not found in
       most csh(1) implementations (specifically, the 4.4BSD csh) are  labeled  with  `(+)',  and
       features which are present in csh(1) but not usually documented are labeled with `(u)'.

   Argument list processing
       If  the first argument (argument 0) to the shell is `-' then it is a login shell.  A login
       shell can be also specified by invoking the shell with the -l flag as the only argument.

       The rest of the flag arguments are interpreted as follows:

       -b  Forces a ``break'' from option processing, causing any further shell arguments  to  be
           treated  as  non-option arguments.  The remaining arguments will not be interpreted as
           shell options.  This may be used to pass options to a shell script  without  confusion
           or  possible  subterfuge.   The  shell  will not run a set-user ID script without this
           option.

       -c  Commands are read from the following argument (which must be present, and  must  be  a
           single  argument),  stored  in the command shell variable for reference, and executed.
           Any remaining arguments are placed in the argv shell variable.

       -d  The shell loads the directory stack from ~/.cshdirs as  described  under  Startup  and
           shutdown, whether or not it is a login shell. (+)

       -Dname[=value]
           Sets the environment variable name to value. (Domain/OS only) (+)

       -e  The shell exits if any invoked command terminates abnormally or yields a non-zero exit
           status.

       -f  The shell does not load any resource or startup files, or perform any command hashing,
           and thus starts faster.

       -F  The shell uses fork(2) instead of vfork(2) to spawn processes. (+)

       -i  The  shell  is  interactive and prompts for its top-level input, even if it appears to
           not be a terminal.  Shells are interactive without this option  if  their  inputs  and
           outputs are terminals.

       -l  The shell is a login shell.  Applicable only if -l is the only flag specified.

       -m  The  shell  loads  ~/.tcshrc  even if it does not belong to the effective user.  Newer
           versions of su(1) can pass -m to the shell. (+)

       -n  The shell parses commands but does not execute them.  This  aids  in  debugging  shell
           scripts.

       -q  The  shell  accepts  SIGQUIT (see Signal handling) and behaves when it is used under a
           debugger.  Job control is disabled. (u)

       -s  Command input is taken from the standard input.

       -t  The shell reads and executes a single line of input.  A `\' may be used to escape  the
           newline at the end of this line and continue onto another line.

       -v  Sets  the  verbose  shell  variable,  so  that  command  input is echoed after history
           substitution.

       -x  Sets the  echo  shell  variable,  so  that  commands  are  echoed  immediately  before
           execution.

       -V  Sets the verbose shell variable even before executing ~/.tcshrc.

       -X  Is to -x as -V is to -v.

       --help
           Print a help message on the standard output and exit. (+)

       --version
           Print  the version/platform/compilation options on the standard output and exit.  This
           information is also contained in the version shell variable. (+)

       After processing of flag arguments, if arguments remain but none of the -c, -i, -s, or  -t
       options  were  given,  the  first  argument is taken as the name of a file of commands, or
       ``script'', to be executed.  The shell opens this file and saves  its  name  for  possible
       resubstitution by `$0'.  Because many systems use either the standard version 6 or version
       7 shells whose shell scripts are not compatible with this shell, the  shell  uses  such  a
       `standard'  shell  to execute a script whose first character is not a `#', i.e., that does
       not start with a comment.

       Remaining arguments are placed in the argv shell variable.

   Startup and shutdown
       A login shell begins by executing  commands  from  the  system  files  /etc/csh.cshrc  and
       /etc/csh.login.   It then executes commands from files in the user's home directory: first
       ~/.tcshrc (+) or, if ~/.tcshrc is not found, ~/.cshrc, then the contents of ~/.history (or
       the  value  of  the  histfile  shell  variable) are loaded into memory, then ~/.login, and
       finally ~/.cshdirs (or the value of the dirsfile shell variable) (+).  The shell may  read
       /etc/csh.login  before  instead  of  after  /etc/csh.cshrc, and ~/.login before instead of
       after ~/.tcshrc or ~/.cshrc  and  ~/.history,  if  so  compiled;  see  the  version  shell
       variable. (+)

       Non-login shells read only /etc/csh.cshrc and ~/.tcshrc or ~/.cshrc on startup.

       For examples of startup files, please consult http://tcshrc.sourceforge.net.

       Commands  like  stty(1)  and tset(1), which need be run only once per login, usually go in
       one's ~/.login file.  Users who need to use the same set of files  with  both  csh(1)  and
       tcsh  can  have  only a ~/.cshrc which checks for the existence of the tcsh shell variable
       (q.v.) before using tcsh-specific commands, or can have both a ~/.cshrc  and  a  ~/.tcshrc
       which  sources  (see  the  builtin  command)  ~/.cshrc.   The  rest  of  this  manual uses
       `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is not found, ~/.cshrc'.

       In the normal case, the shell begins reading commands from the terminal, prompting with `>
       '.   (Processing of arguments and the use of the shell to process files containing command
       scripts are described later.)  The shell repeatedly reads a line of command input,  breaks
       it  into words, places it on the command history list, parses it and executes each command
       in the line.

       One can log out by typing `^D' on an empty line, `logout' or `login' or  via  the  shell's
       autologout  mechanism  (see the autologout shell variable).  When a login shell terminates
       it sets the logout shell variable to `normal' or `automatic' as appropriate, then executes
       commands  from  the files /etc/csh.logout and ~/.logout.  The shell may drop DTR on logout
       if so compiled; see the version shell variable.

       The names  of  the  system  login  and  logout  files  vary  from  system  to  system  for
       compatibility with different csh(1) variants; see FILES.

   Editing
       We  first  describe  The  command-line  editor.   The  Completion and listing and Spelling
       correction sections describe two sets of functionality  that  are  implemented  as  editor
       commands  but  which  deserve  their  own  treatment.   Finally, Editor commands lists and
       describes the editor commands specific to the shell and their default bindings.

   The command-line editor (+)
       Command-line input can be edited using key sequences much like those used in  emacs(1)  or
       vi(1).   The  editor  is  active  only when the edit shell variable is set, which it is by
       default in interactive shells.  The bindkey builtin can display and change  key  bindings.
       emacs(1)-style  key bindings are used by default (unless the shell was compiled otherwise;
       see the version shell variable), but bindkey can change the key  bindings  to  vi(1)-style
       bindings en masse.

       The shell always binds the arrow keys (as defined in the TERMCAP environment variable) to

           down    down-history
           up      up-history
           left    backward-char
           right   forward-char

       unless  doing  so would alter another single-character binding.  One can set the arrow key
       escape sequences to the empty string with settc to prevent these bindings.  The ANSI/VT100
       sequences for arrow keys are always bound.

       Other  key bindings are, for the most part, what emacs(1) and vi(1) users would expect and
       can easily be displayed by bindkey, so there is no need  to  list  them  here.   Likewise,
       bindkey  can  list  the  editor  commands  with  a short description of each.  Certain key
       bindings have different behavior depending if emacs(1) or vi(1) style bindings  are  being
       used; see vimode for more information.

       Note  that  editor  commands  do not have the same notion of a ``word'' as does the shell.
       The editor delimits words with any non-alphanumeric characters not in the  shell  variable
       wordchars,  while  the  shell  recognizes  only whitespace and some of the characters with
       special meanings to it, listed under Lexical structure.

   Completion and listing (+)
       The shell is often able to complete words when given a unique abbreviation.  Type part  of
       a  word  (for  example `ls /usr/lost') and hit the tab key to run the complete-word editor
       command.  The shell completes the filename `/usr/lost'  to  `/usr/lost+found/',  replacing
       the  incomplete  word with the complete word in the input buffer.  (Note the terminal `/';
       completion adds a `/' to the end of completed directories and a space to the end of  other
       completed  words, to speed typing and provide a visual indicator of successful completion.
       The addsuffix shell variable can be unset to prevent this.)  If no match is found (perhaps
       `/usr/lost+found'  doesn't  exist),  the  terminal  bell  rings.   If  the word is already
       complete (perhaps there is a `/usr/lost' on your system, or perhaps you were thinking  too
       far  ahead  and  typed  the  whole  thing)  a `/' or space is added to the end if it isn't
       already there.

       Completion works anywhere in the line, not at just the end; completed text pushes the rest
       of  the  line  to the right.  Completion in the middle of a word often results in leftover
       characters to the right of the cursor that need to be deleted.

       Commands and variables can be completed  in  much  the  same  way.   For  example,  typing
       `em[tab]'  would  complete  `em'  to `emacs' if emacs were the only command on your system
       beginning with `em'.  Completion can find a command in any directory in path or if given a
       full  pathname.   Typing  `echo  $ar[tab]'  would  complete  `$ar'  to `$argv' if no other
       variable began with `ar'.

       The shell parses the input buffer to determine whether  the  word  you  want  to  complete
       should  be completed as a filename, command or variable.  The first word in the buffer and
       the first word following `;', `|', `|&', `&&' or `||' is considered to be  a  command.   A
       word  beginning with `$' is considered to be a variable.  Anything else is a filename.  An
       empty line is `completed' as a filename.

       You can list the possible completions of a word at any time by  typing  `^D'  to  run  the
       delete-char-or-list-or-eof editor command.  The shell lists the possible completions using
       the ls-F builtin (q.v.)  and reprints the prompt and unfinished command line, for example:

           > ls /usr/l[^D]
           lbin/       lib/        local/      lost+found/
           > ls /usr/l

       If the autolist shell variable is set, the shell lists  the  remaining  choices  (if  any)
       whenever completion fails:

           > set autolist
           > nm /usr/lib/libt[tab]
           libtermcap.a@ libtermlib.a@
           > nm /usr/lib/libterm

       If  autolist is set to `ambiguous', choices are listed only when completion fails and adds
       no new characters to the word being completed.

       A filename to be completed can contain variables, your own  or  others'  home  directories
       abbreviated  with  `~' (see Filename substitution) and directory stack entries abbreviated
       with `=' (see Directory stack substitution).  For example,

           > ls ~k[^D]
           kahn    kas     kellogg
           > ls ~ke[tab]
           > ls ~kellogg/

       or

           > set local = /usr/local
           > ls $lo[tab]
           > ls $local/[^D]
           bin/ etc/ lib/ man/ src/
           > ls $local/

       Note that variables can also be  expanded  explicitly  with  the  expand-variables  editor
       command.

       delete-char-or-list-or-eof  lists  at only the end of the line; in the middle of a line it
       deletes the character under the cursor and on an  empty  line  it  logs  one  out  or,  if
       ignoreeof  is  set, does nothing.  `M-^D', bound to the editor command list-choices, lists
       completion possibilities anywhere on a line, and list-choices (or any one of  the  related
       editor commands that do or don't delete, list and/or log out, listed under delete-char-or-
       list-or-eof) can be bound to `^D' with the bindkey builtin command if so desired.

       The complete-word-fwd and complete-word-back editor commands (not bound  to  any  keys  by
       default)  can  be  used  to  cycle  up  and down through the list of possible completions,
       replacing the current word with the next or previous word in the list.

       The shell variable fignore can be set to a list of suffixes to be ignored  by  completion.
       Consider the following:

           > ls
           Makefile        condiments.h~   main.o          side.c
           README          main.c          meal            side.o
           condiments.h    main.c~
           > set fignore = (.o \~)
           > emacs ma[^D]
           main.c   main.c~  main.o
           > emacs ma[tab]
           > emacs main.c

       `main.c~'  and  `main.o'  are ignored by completion (but not listing), because they end in
       suffixes in fignore.  Note that a `\' was needed in front of `~' to prevent it from  being
       expanded to home as described under Filename substitution.  fignore is ignored if only one
       completion is possible.

       If the complete shell variable is set to `enhance', completion  1)  ignores  case  and  2)
       considers  periods,  hyphens  and underscores (`.', `-' and `_') to be word separators and
       hyphens and underscores to be equivalent.  If you had the following files

           comp.lang.c      comp.lang.perl   comp.std.c++
           comp.lang.c++    comp.std.c

       and typed `mail -f c.l.c[tab]', it would be completed to `mail  -f  comp.lang.c',  and  ^D
       would   list   `comp.lang.c'   and  `comp.lang.c++'.   `mail  -f  c..c++[^D]'  would  list
       `comp.lang.c++' and `comp.std.c++'.  Typing `rm a--file[^D]' in the following directory

           A_silly_file    a-hyphenated-file    another_silly_file

       would list all three files, because case  is  ignored  and  hyphens  and  underscores  are
       equivalent.  Periods, however, are not equivalent to hyphens or underscores.

       If  the  complete  shell  variable  is  set  to  `Enhance',  completion  ignores  case and
       differences between a hyphen and an underscore word separator only when the user  types  a
       lowercase  character  or  a hyphen.  Entering an uppercase character or an underscore will
       not match the corresponding lowercase character or  hyphen  word  separator.   Typing  `rm
       a--file[^D]'  in  the  directory of the previous example would still list all three files,
       but typing `rm A--file' would match only `A_silly_file' and typing `rm a__file[^D]'  would
       match  just  `A_silly_file'  and  `another_silly_file' because the user explicitly used an
       uppercase or an underscore character.

       Completion and listing are affected by several other shell variables: recexact can be  set
       to  complete  on the shortest possible unique match, even if more typing might result in a
       longer match:

           > ls
           fodder   foo      food     foonly
           > set recexact
           > rm fo[tab]

       just beeps, because `fo' could expand to `fod' or `foo', but if we type another `o',

           > rm foo[tab]
           > rm foo

       the completion completes on `foo', even though `food' and `foonly' also match.  autoexpand
       can  be  set  to  run  the  expand-history  editor command before each completion attempt,
       autocorrect can be set  to  spelling-correct  the  word  to  be  completed  (see  Spelling
       correction)  before  each  completion  attempt and correct can be set to complete commands
       automatically after one hits `return'.  matchbeep can be set to make  completion  beep  or
       not  beep  in a variety of situations, and nobeep can be set to never beep at all.  nostat
       can be set to a list of directories and/or patterns that match directories to prevent  the
       completion  mechanism  from  stat(2)ing those directories.  listmax and listmaxrows can be
       set to limit the number of items and rows (respectively) that are  listed  without  asking
       first.  recognize_only_executables can be set to make the shell list only executables when
       listing commands, but it is quite slow.

       Finally, the complete builtin command can be used to tell the shell how to complete  words
       other than filenames, commands and variables.  Completion and listing do not work on glob-
       patterns (see Filename substitution), but the list-glob and  expand-glob  editor  commands
       perform equivalent functions for glob-patterns.

   Spelling correction (+)
       The  shell can sometimes correct the spelling of filenames, commands and variable names as
       well as completing and listing them.

       Individual words can be spelling-corrected with the  spell-word  editor  command  (usually
       bound  to M-s and M-S) and the entire input buffer with spell-line (usually bound to M-$).
       The correct shell variable can be set to `cmd' to correct the command  name  or  `all'  to
       correct  the  entire line each time return is typed, and autocorrect can be set to correct
       the word to be completed before each completion attempt.

       When spelling correction is invoked in any of these ways and the  shell  thinks  that  any
       part of the command line is misspelled, it prompts with the corrected line:

           > set correct = cmd
           > lz /usr/bin
           CORRECT>ls /usr/bin (y|n|e|a)?

       One  can  answer  `y' or space to execute the corrected line, `e' to leave the uncorrected
       command in the input buffer, `a' to abort the  command  as  if  `^C'  had  been  hit,  and
       anything else to execute the original line unchanged.

       Spelling   correction  recognizes  user-defined  completions  (see  the  complete  builtin
       command).  If an input word in a position for which a completion is  defined  resembles  a
       word  in the completion list, spelling correction registers a misspelling and suggests the
       latter word as a correction.  However, if the  input  word  does  not  match  any  of  the
       possible   completions  for  that  position,  spelling  correction  does  not  register  a
       misspelling.

       Like completion, spelling correction works anywhere in the line, pushing the rest  of  the
       line to the right and possibly leaving extra characters to the right of the cursor.

   Editor commands (+)
       `bindkey' lists key bindings and `bindkey -l' lists and briefly describes editor commands.
       Only new or especially interesting editor commands are described here.  See  emacs(1)  and
       vi(1) for descriptions of each editor's key bindings.

       The  character  or  characters  to  which  each  command  is  bound by default is given in
       parentheses.  `^character' means a control character and `M-character' a  meta  character,
       typed as escape-character on terminals without a meta key.  Case counts, but commands that
       are bound to letters by default are  bound  to  both  lower-  and  uppercase  letters  for
       convenience.

       backward-char (^B, left)
               Move back a character.  Cursor behavior modified by vimode.

       backward-delete-word (M-^H, M-^?)
               Cut from beginning of current word to cursor - saved in cut buffer.  Word boundary
               behavior modified by vimode.

       backward-word (M-b, M-B)
               Move to beginning of current word.  Word boundary and cursor behavior modified  by
               vimode.

       beginning-of-line (^A, home)
               Move to beginning of line.  Cursor behavior modified by vimode.

       capitalize-word (M-c, M-C)
               Capitalize  the  characters  from  cursor  to  end of current word.  Word boundary
               behavior modified by vimode.

       complete-word (tab)
               Completes a word as described under Completion and listing.

       complete-word-back (not bound)
               Like complete-word-fwd, but steps up from the end of the list.

       complete-word-fwd (not bound)
               Replaces the current word with the first word in the list of possible completions.
               May  be repeated to step down through the list.  At the end of the list, beeps and
               reverts to the incomplete word.

       complete-word-raw (^X-tab)
               Like complete-word, but ignores user-defined completions.

       copy-prev-word (M-^_)
               Copies the previous word in the current line into  the  input  buffer.   See  also
               insert-last-word.  Word boundary behavior modified by vimode.

       dabbrev-expand (M-/)
               Expands the current word to the most recent preceding one for which the current is
               a leading substring,  wrapping  around  the  history  list  (once)  if  necessary.
               Repeating  dabbrev-expand  without  any  intervening  typing  changes  to the next
               previous word etc., skipping identical matches much  like  history-search-backward
               does.

       delete-char (bound to `Del' if using the standard /etc/csh.cshrc)
               Deletes  the  character  under  the  cursor.  See also delete-char-or-list-or-eof.
               Cursor behavior modified by vimode.

       delete-char-or-eof (not bound)
               Does delete-char if there is a character under the cursor  or  end-of-file  on  an
               empty  line.   See  also  delete-char-or-list-or-eof.  Cursor behavior modified by
               vimode.

       delete-char-or-list (not bound)
               Does delete-char if there is a character under the cursor or list-choices  at  the
               end of the line.  See also delete-char-or-list-or-eof.

       delete-char-or-list-or-eof (^D)
               Does delete-char if there is a character under the cursor, list-choices at the end
               of the line or end-of-file on an empty line.  See also those three commands,  each
               of  which  does  only a single action, and delete-char-or-eof, delete-char-or-list
               and list-or-eof, each of which does a different two out of the three.

       delete-word (M-d, M-D)
               Cut from cursor to end of current word  -  save  in  cut  buffer.   Word  boundary
               behavior modified by vimode.

       down-history (down-arrow, ^N)
               Like up-history, but steps down, stopping at the original input line.

       downcase-word (M-l, M-L)
               Lowercase  the  characters  from  cursor  to  end  of current word.  Word boundary
               behavior modified by vimode.

       end-of-file (not bound)
               Signals an end of file, causing the shell  to  exit  unless  the  ignoreeof  shell
               variable (q.v.) is set to prevent this.  See also delete-char-or-list-or-eof.

       end-of-line (^E, end)
               Move cursor to end of line.  Cursor behavior modified by vimode.

       expand-history (M-space)
               Expands history substitutions in the current word.  See History substitution.  See
               also magic-space, toggle-literal-history and the autoexpand shell variable.

       expand-glob (^X-*)
               Expands the glob-pattern to the left of the cursor.  See Filename substitution.

       expand-line (not bound)
               Like expand-history, but expands history substitutions in each word in  the  input
               buffer.

       expand-variables (^X-$)
               Expands the variable to the left of the cursor.  See Variable substitution.

       forward-char (^F, right)
               Move forward one character.  Cursor behavior modified by vimode.

       forward-word (M-f, M-F)
               Move  forward  to end of current word.  Word boundary and cursor behavior modified
               by vimode.

       history-search-backward (M-p, M-P)
               Searches backwards through the history list  for  a  command  beginning  with  the
               current contents of the input buffer up to the cursor and copies it into the input
               buffer.  The search string may  be  a  glob-pattern  (see  Filename  substitution)
               containing  `*', `?', `[]' or `{}'.  up-history and down-history will proceed from
               the appropriate point in the history list.  Emacs mode only.   See  also  history-
               search-forward and i-search-back.

       history-search-forward (M-n, M-N)
               Like history-search-backward, but searches forward.

       i-search-back (not bound)
               Searches  backward  like  history-search-backward, copies the first match into the
               input buffer with the cursor positioned at the end of  the  pattern,  and  prompts
               with  `bck:  '  and the first match.  Additional characters may be typed to extend
               the search, i-search-back may  be  typed  to  continue  searching  with  the  same
               pattern,  wrapping  around  the  history list if necessary, (i-search-back must be
               bound to a single character for this to work) or  one  of  the  following  special
               characters may be typed:

                   ^W      Appends the rest of the word under the cursor to the search pattern.
                   delete (or any character bound to backward-delete-char)
                           Undoes  the effect of the last character typed and deletes a character
                           from the search pattern if appropriate.
                   ^G      If the previous search was successful, aborts the entire  search.   If
                           not, goes back to the last successful search.
                   escape  Ends the search, leaving the current line in the input buffer.

               Any  other  character  not  bound  to  self-insert-command  terminates the search,
               leaving the current line in the input buffer, and is then  interpreted  as  normal
               input.   In  particular, a carriage return causes the current line to be executed.
               See  also  i-search-fwd  and  history-search-backward.   Word  boundary   behavior
               modified by vimode.

       i-search-fwd (not bound)
               Like  i-search-back,  but  searches  forward.   Word boundary behavior modified by
               vimode.

       insert-last-word (M-_)
               Inserts the last word of the previous input line (`!$')  into  the  input  buffer.
               See also copy-prev-word.

       list-choices (M-^D)
               Lists  completion  possibilities  as  described under Completion and listing.  See
               also delete-char-or-list-or-eof and list-choices-raw.

       list-choices-raw (^X-^D)
               Like list-choices, but ignores user-defined completions.

       list-glob (^X-g, ^X-G)
               Lists  (via  the  ls-F  builtin)  matches  to  the  glob-pattern   (see   Filename
               substitution) to the left of the cursor.

       list-or-eof (not bound)
               Does  list-choices or end-of-file on an empty line.  See also delete-char-or-list-
               or-eof.

       magic-space (not bound)
               Expands history substitutions  in  the  current  line,  like  expand-history,  and
               inserts a space.  magic-space is designed to be bound to the space bar, but is not
               bound by default.

       normalize-command (^X-?)
               Searches for the current word in PATH and, if it is found, replaces  it  with  the
               full path to the executable.  Special characters are quoted.  Aliases are expanded
               and quoted but commands within aliases are  not.   This  command  is  useful  with
               commands that take commands as arguments, e.g., `dbx' and `sh -x'.

       normalize-path (^X-n, ^X-N)
               Expands  the  current word as described under the `expand' setting of the symlinks
               shell variable.

       overwrite-mode (unbound)
               Toggles between input and overwrite modes.

       run-fg-editor (M-^Z)
               Saves the current input line and looks for a  stopped  job  where  the  file  name
               portion  of  its first word is found in the editors shell variable.  If editors is
               not set, then the file name portion of the EDITOR environment  variable  (`ed'  if
               unset)  and the VISUAL environment variable (`vi' if unset) will be used.  If such
               a job is found, it is restarted as if `fg %job' had been typed.  This is  used  to
               toggle  back  and  forth between an editor and the shell easily.  Some people bind
               this command to `^Z' so they can do this even more easily.

       run-help (M-h, M-H)
               Searches for documentation on the  current  command,  using  the  same  notion  of
               `current  command'  as the completion routines, and prints it.  There is no way to
               use a pager; run-help is designed for short help  files.   If  the  special  alias
               helpcommand is defined, it is run with the command name as a sole argument.  Else,
               documentation should be  in  a  file  named  command.help,  command.1,  command.6,
               command.8  or  command,  which  should  be in one of the directories listed in the
               HPATH environment variable.  If there is more than one help file only the first is
               printed.

       self-insert-command (text characters)
               In  insert  mode  (the  default),  inserts the typed character into the input line
               after the character under the cursor.  In overwrite mode, replaces  the  character
               under  the  cursor with the typed character.  The input mode is normally preserved
               between lines, but the  inputmode  shell  variable  can  be  set  to  `insert'  or
               `overwrite'  to  put  the  editor in that mode at the beginning of each line.  See
               also overwrite-mode.

       sequence-lead-in (arrow prefix, meta prefix, ^X)
               Indicates that the following characters are part of a multi-key sequence.  Binding
               a command to a multi-key sequence really creates two bindings: the first character
               to sequence-lead-in  and  the  whole  sequence  to  the  command.   All  sequences
               beginning  with  a  character  bound  to sequence-lead-in are effectively bound to
               undefined-key unless bound to another command.

       spell-line (M-$)
               Attempts to correct the spelling of each word in the  input  buffer,  like  spell-
               word,  but  ignores words whose first character is one of `-', `!', `^' or `%', or
               which contain `\', `*' or `?', to avoid problems with switches, substitutions  and
               the like.  See Spelling correction.

       spell-word (M-s, M-S)
               Attempts  to  correct the spelling of the current word as described under Spelling
               correction.  Checks each component of a word which appears to be a pathname.

       toggle-literal-history (M-r, M-R)
               Expands or `unexpands' history  substitutions  in  the  input  buffer.   See  also
               expand-history and the autoexpand shell variable.

       undefined-key (any unbound key)
               Beeps.

       up-history (up-arrow, ^P)
               Copies  the  previous entry in the history list into the input buffer.  If histlit
               is set, uses the literal form of the entry.  May be repeated to  step  up  through
               the history list, stopping at the top.

       upcase-word (M-u, M-U)
               Uppercase  the  characters  from  cursor  to  end  of current word.  Word boundary
               behavior modified by vimode.

       vi-beginning-of-next-word (not bound)
               Vi goto the beginning of next word.  Word boundary and cursor behavior modified by
               vimode.

       vi-eword (not bound)
               Vi  move  to  the  end  of  the  current word.  Word boundary behavior modified by
               vimode.

       vi-search-back (?)
               Prompts with `?' for a search  string  (which  may  be  a  glob-pattern,  as  with
               history-search-backward),  searches  for  it  and copies it into the input buffer.
               The bell rings if no match is found.  Hitting return ends the  search  and  leaves
               the  last  match in the input buffer.  Hitting escape ends the search and executes
               the match.  vi mode only.

       vi-search-fwd (/)
               Like vi-search-back, but searches forward.

       which-command (M-?)
               Does a which (see the description of the builtin command) on the first word of the
               input buffer.

       yank-pop (M-y)
               When  executed  immediately  after a yank or another yank-pop, replaces the yanked
               string with the next previous string from the killring. This also has  the  effect
               of  rotating  the  killring,  such  that  this  string will be considered the most
               recently killed by a later yank command. Repeating yank-pop will cycle through the
               killring any number of times.

   Lexical structure
       The  shell  splits input lines into words at blanks and tabs.  The special characters `&',
       `|', `;', `<', `>', `(', and `)' and the doubled characters `&&', `||', `<<' and `>>'  are
       always separate words, whether or not they are surrounded by whitespace.

       When  the  shell's input is not a terminal, the character `#' is taken to begin a comment.
       Each `#' and the rest of the input line on which it appears is  discarded  before  further
       parsing.

       A  special  character  (including a blank or tab) may be prevented from having its special
       meaning, and possibly made part of another word, by preceding it with a backslash (`\') or
       enclosing  it  in single (`''), double (`"') or backward (``') quotes.  When not otherwise
       quoted a newline preceded by a `\' is equivalent  to  a  blank,  but  inside  quotes  this
       sequence results in a newline.

       Furthermore, all Substitutions (see below) except History substitution can be prevented by
       enclosing the strings (or parts of strings) in which they appear with single quotes or  by
       quoting  the  crucial  character(s) (e.g., `$' or ``' for Variable substitution or Command
       substitution respectively) with `\'.  (Alias substitution is no exception: quoting in  any
       way  any  character of a word for which an alias has been defined prevents substitution of
       the alias.  The usual way of quoting an alias is to precede it with a backslash.)  History
       substitution  is  prevented  by backslashes but not by single quotes.  Strings quoted with
       double or backward quotes undergo Variable  substitution  and  Command  substitution,  but
       other substitutions are prevented.

       Text   inside   single  or  double  quotes  becomes  a  single  word  (or  part  of  one).
       Metacharacters in these strings, including blanks and tabs, do not  form  separate  words.
       Only in one special case (see Command substitution below) can a double-quoted string yield
       parts of more than one word; single-quoted strings never do.  Backward quotes are special:
       they signal Command substitution (q.v.), which may result in more than one word.

       Quoting complex strings, particularly strings which themselves contain quoting characters,
       can be confusing.  Remember that quotes need not be used as they are in human writing!  It
       may be easier to quote not an entire string, but only those parts of the string which need
       quoting, using different types of quoting to do so if appropriate.

       The backslash_quote shell variable (q.v.) can be set to make backslashes always quote `\',
       `'',  and  `"'.   (+)  This may make complex quoting tasks easier, but it can cause syntax
       errors in csh(1) scripts.

   Substitutions
       We now describe the various transformations the shell performs on the input in  the  order
       in which they occur.  We note in passing the data structures involved and the commands and
       variables which affect them.  Remember that substitutions can be prevented by  quoting  as
       described under Lexical structure.

   History substitution
       Each  command,  or  ``event'',  input from the terminal is saved in the history list.  The
       previous command is always saved, and the history shell variable can be set to a number to
       save  that  many  commands.   The  histdup shell variable can be set to not save duplicate
       events or consecutive duplicate events.

       Saved commands are numbered sequentially from 1 and stamped with  the  time.   It  is  not
       usually  necessary  to use event numbers, but the current event number can be made part of
       the prompt by placing an `!' in the prompt shell variable.

       The shell actually saves history in expanded  and  literal  (unexpanded)  forms.   If  the
       histlit  shell  variable  is  set, commands that display and store history use the literal
       form.

       The history builtin command can print, store in a file, restore and clear the history list
       at any time, and the savehist and histfile shell variables can be set to store the history
       list automatically on logout and restore it on login.

       History substitutions introduce words from the history list into the input stream,  making
       it easy to repeat commands, repeat arguments of a previous command in the current command,
       or fix spelling mistakes in the previous command with little typing and a high  degree  of
       confidence.

       History  substitutions begin with the character `!'.  They may begin anywhere in the input
       stream, but they do not nest.  The `!' may be preceded by a `\'  to  prevent  its  special
       meaning;  for  convenience, a `!' is passed unchanged when it is followed by a blank, tab,
       newline, `=' or `('.  History substitutions also occur when an input line begins with `^'.
       This  special abbreviation will be described later.  The characters used to signal history
       substitution (`!' and `^') can be changed by setting the histchars  shell  variable.   Any
       input line which contains a history substitution is printed before it is executed.

       A history substitution may have an ``event specification'', which indicates the event from
       which words are to be taken, a ``word designator'', which selects  particular  words  from
       the chosen event, and/or a ``modifier'', which manipulates the selected words.

       An event specification can be

           n       A number, referring to a particular event
           -n      An offset, referring to the event n before the current event
           #       The current event.  This should be used carefully in csh(1), where there is no
                   check for recursion.  tcsh allows 10 levels of recursion.  (+)
           !       The previous event (equivalent to `-1')
           s       The most recent event whose first word begins with the string s
           ?s?     The most recent event which contains the string s.   The  second  `?'  can  be
                   omitted if it is immediately followed by a newline.

       For example, consider this bit of someone's history list:

            9  8:30    nroff -man wumpus.man
           10  8:31    cp wumpus.man wumpus.man.old
           11  8:36    vi wumpus.man
           12  8:37    diff wumpus.man.old wumpus.man

       The commands are shown with their event numbers and time stamps.  The current event, which
       we haven't typed in yet, is event 13.  `!11' and `!-2' refer to event 11.  `!!' refers  to
       the  previous  event,  12.   `!!'  can be abbreviated `!' if it is followed by `:' (`:' is
       described below).  `!n' refers to event 9, which begins with `n'.  `!?old?' also refers to
       event  12, which contains `old'.  Without word designators or modifiers history references
       simply expand to the entire event, so we might type `!cp' to  redo  the  copy  command  or
       `!!|more' if the `diff' output scrolled off the top of the screen.

       History  references  may  be insulated from the surrounding text with braces if necessary.
       For example, `!vdoc' would look for a command beginning with `vdoc', and, in this example,
       not  find  one,  but  `!{v}doc' would expand unambiguously to `vi wumpus.mandoc'.  Even in
       braces, history substitutions do not nest.

       (+) While csh(1) expands, for example, `!3d' to event 3 with the letter  `d'  appended  to
       it,  tcsh  expands  it  to  the  last  event  beginning with `3d'; only completely numeric
       arguments are treated as event numbers.  This makes it possible to recall events beginning
       with numbers.  To expand `!3d' as in csh(1) say `!{3}d'.

       To  select  words  from  an  event  we  can  follow the event specification by a `:' and a
       designator for the desired words.  The words of an input line are  numbered  from  0,  the
       first  (usually command) word being 0, the second word (first argument) being 1, etc.  The
       basic word designators are:

           0       The first (command) word
           n       The nth argument
           ^       The first argument, equivalent to `1'
           $       The last argument
           %       The word matched by an ?s? search
           x-y     A range of words
           -y      Equivalent to `0-y'
           *       Equivalent to `^-$', but returns nothing if the event contains only 1 word
           x*      Equivalent to `x-$'
           x-      Equivalent to `x*', but omitting the last word (`$')

       Selected words are inserted into  the  command  line  separated  by  single  blanks.   For
       example,  the  `diff'  command  in  the  previous  example  might have been typed as `diff
       !!:1.old !!:1' (using `:1' to select the first argument from the previous event) or  `diff
       !-2:2  !-2:1'  to  select and swap the arguments from the `cp' command.  If we didn't care
       about the order of the `diff' we might have said `diff !-2:1-2' or  simply  `diff  !-2:*'.
       The  `cp'  command might have been written `cp wumpus.man !#:1.old', using `#' to refer to
       the current event.  `!n:- hurkle.man' would reuse the first two  words  from  the  `nroff'
       command to say `nroff -man hurkle.man'.

       The  `:' separating the event specification from the word designator can be omitted if the
       argument selector begins with a `^', `$', `*',  `%'  or  `-'.   For  example,  our  `diff'
       command might have been `diff !!^.old !!^' or, equivalently, `diff !!$.old !!$'.  However,
       if `!!' is abbreviated `!', an argument selector beginning with `-' will be interpreted as
       an event specification.

       A  history  reference  may  have  a  word  designator but no event specification.  It then
       references the previous command.  Continuing our `diff' example, we could have said simply
       `diff !^.old !^' or, to get the arguments in the opposite order, just `diff !*'.

       The  word  or words in a history reference can be edited, or ``modified'', by following it
       with one or more modifiers, each preceded by a `:':

           h       Remove a trailing pathname component, leaving the head.
           t       Remove all leading pathname components, leaving the tail.
           r       Remove a filename extension `.xxx', leaving the root name.
           e       Remove all but the extension.
           u       Uppercase the first lowercase letter.
           l       Lowercase the first uppercase letter.
           s/l/r/  Substitute l for r.  l is simply a string like r, not a regular expression  as
                   in the eponymous ed(1) command.  Any character may be used as the delimiter in
                   place of `/'; a `\' can be used to quote the delimiter inside l  and  r.   The
                   character  `&'  in the r is replaced by l; `\' also quotes `&'.  If l is empty
                   (``''), the l from a previous substitution or the s from a previous search  or
                   event  number  in  event specification is used.  The trailing delimiter may be
                   omitted if it is immediately followed by a newline.
           &       Repeat the previous substitution.
           g       Apply the following modifier once to each word.
           a (+)   Apply the following modifier as many times as possible to a single word.   `a'
                   and  `g'  can  be  used  together  to apply a modifier globally.  With the `s'
                   modifier, only the patterns contained in the original  word  are  substituted,
                   not patterns that contain any substitution result.
           p       Print the new command line but do not execute it.
           q       Quote the substituted words, preventing further substitutions.
           x       Like q, but break into words at blanks, tabs and newlines.

       Modifiers  are  applied  to only the first modifiable word (unless `g' is used).  It is an
       error for no word to be modifiable.

       For example, the `diff' command might have been written as  `diff  wumpus.man.old  !#^:r',
       using  `:r'  to  remove `.old' from the first argument on the same line (`!#^').  We could
       say `echo hello out there', then `echo !*:u' to capitalize `hello', `echo !*:au' to say it
       out  loud,  or  `echo  !*:agu'  to  really  shout.   We might follow `mail -s "I forgot my
       password" rot' with `!:s/rot/root' to correct the spelling of  `root'  (but  see  Spelling
       correction for a different approach).

       There is a special abbreviation for substitutions.  `^', when it is the first character on
       an input line, is equivalent to `!:s^'.  Thus we might have said `^rot^root' to  make  the
       spelling  correction in the previous example.  This is the only history substitution which
       does not explicitly begin with `!'.

       (+) In csh as such, only  one  modifier  may  be  applied  to  each  history  or  variable
       expansion.  In tcsh, more than one may be used, for example

           % mv wumpus.man /usr/man/man1/wumpus.1
           % man !$:t:r
           man wumpus

       In  csh, the result would be `wumpus.1:r'.  A substitution followed by a colon may need to
       be insulated from it with braces:

           > mv a.out /usr/games/wumpus
           > setenv PATH !$:h:$PATH
           Bad ! modifier: $.
           > setenv PATH !{-2$:h}:$PATH
           setenv PATH /usr/games:/bin:/usr/bin:.

       The first attempt would succeed in csh but fails in tcsh,  because  tcsh  expects  another
       modifier after the second colon rather than `$'.

       Finally,  history  can be accessed through the editor as well as through the substitutions
       just described.  The up- and down-history, history-search-backward and -forward, i-search-
       back  and  -fwd,  vi-search-back  and  -fwd,  copy-prev-word  and  insert-last-word editor
       commands search for events in the history list and copy them into the input  buffer.   The
       toggle-literal-history  editor  command switches between the expanded and literal forms of
       history lines  in  the  input  buffer.   expand-history  and  expand-line  expand  history
       substitutions in the current word and in the entire input buffer respectively.

   Alias substitution
       The shell maintains a list of aliases which can be set, unset and printed by the alias and
       unalias commands.  After a command line is parsed into simple commands (see Commands)  the
       first  word  of each command, left-to-right, is checked to see if it has an alias.  If so,
       the first word is replaced by the alias.  If the alias contains a  history  reference,  it
       undergoes  History  substitution  (q.v.)  as though the original command were the previous
       input line.  If the alias does not contain a history reference, the argument list is  left
       untouched.

       Thus  if  the alias for `ls' were `ls -l' the command `ls /usr' would become `ls -l /usr',
       the argument list here being undisturbed.   If  the  alias  for  `lookup'  were  `grep  !^
       /etc/passwd' then `lookup bill' would become `grep bill /etc/passwd'.  Aliases can be used
       to introduce parser metasyntax.  For example, `alias print  'pr  \!*  |  lpr''  defines  a
       ``command'' (`print') which pr(1)s its arguments to the line printer.

       Alias  substitution  is  repeated until the first word of the command has no alias.  If an
       alias substitution does not change the first word (as  in  the  previous  example)  it  is
       flagged to prevent a loop.  Other loops are detected and cause an error.

       Some aliases are referred to by the shell; see Special aliases.

   Variable substitution
       The shell maintains a list of variables, each of which has as value a list of zero or more
       words.  The values of shell variables can be displayed and changed with the set and  unset
       commands.   The  system maintains its own list of ``environment'' variables.  These can be
       displayed and changed with printenv, setenv and unsetenv.

       (+) Variables may be made read-only with `set -r' (q.v.).  Read-only variables may not  be
       modified  or  unset;  attempting  to  do  so  will cause an error.  Once made read-only, a
       variable cannot be made writable, so `set -r' should be used  with  caution.   Environment
       variables cannot be made read-only.

       Some variables are set by the shell or referred to by it.  For instance, the argv variable
       is an image of the shell's argument list, and words of this variable's value are  referred
       to in special ways.  Some of the variables referred to by the shell are toggles; the shell
       does not care what their value is, only whether they are set or not.   For  instance,  the
       verbose variable is a toggle which causes command input to be echoed.  The -v command line
       option sets this variable.  Special shell variables lists all variables which are referred
       to by the shell.

       Other   operations   treat   variables  numerically.   The  `@'  command  permits  numeric
       calculations to be performed and the result assigned to a variable.  Variable values  are,
       however,  always  represented  as  (zero  or  more)  strings.  For the purposes of numeric
       operations, the null string is considered to be zero, and the second and subsequent  words
       of multi-word values are ignored.

       After  the input line is aliased and parsed, and before each command is executed, variable
       substitution is performed keyed by `$' characters.  This expansion  can  be  prevented  by
       preceding  the  `$'  with a `\' except within `"'s where it always occurs, and within `''s
       where it never  occurs.   Strings  quoted  by  ``'  are  interpreted  later  (see  Command
       substitution  below)  so  `$' substitution does not occur there until later, if at all.  A
       `$' is passed unchanged if followed by a blank, tab, or end-of-line.

       Input/output redirections are recognized  before  variable  expansion,  and  are  variable
       expanded  separately.   Otherwise,  the command name and entire argument list are expanded
       together.  It is thus possible for the first (command) word (to this  point)  to  generate
       more  than  one  word,  the first of which becomes the command name, and the rest of which
       become arguments.

       Unless enclosed in `"' or given the `:q' modifier the results of variable substitution may
       eventually  be  command  and  filename  substituted.   Within  `"', a variable whose value
       consists of multiple words expands to a (portion of a) single word, with the words of  the
       variable's value separated by blanks.  When the `:q' modifier is applied to a substitution
       the variable will expand to multiple words with each word separated by a blank and  quoted
       to prevent later command or filename substitution.

       The  following  metasequences  are provided for introducing variable values into the shell
       input.  Except as noted, it is an error to reference a variable which is not set.

       $name
       ${name} Substitutes the words of the value of variable name, each separated  by  a  blank.
               Braces  insulate  name  from following characters which would otherwise be part of
               it.  Shell variables have names consisting of letters and digits starting  with  a
               letter.   The underscore character is considered a letter.  If name is not a shell
               variable, but is set in the environment, then that value is returned (but some  of
               the other forms given below are not available in this case).
       $name[selector]
       ${name[selector]}
               Substitutes  only  the  selected  words  from  the value of name.  The selector is
               subjected to `$' substitution and may consist of a single number  or  two  numbers
               separated by a `-'.  The first word of a variable's value is numbered `1'.  If the
               first number of a range is omitted it defaults to `1'.  If the last  member  of  a
               range is omitted it defaults to `$#name'.  The selector `*' selects all words.  It
               is not an error for a range to be empty if the second argument is  omitted  or  in
               range.
       $0      Substitutes the name of the file from which command input is being read.  An error
               occurs if the name is not known.
       $number
       ${number}
               Equivalent to `$argv[number]'.
       $*      Equivalent to `$argv', which is equivalent to `$argv[*]'.

       The `:' modifiers described under History substitution, except for `:p', can be applied to
       the substitutions above.  More than one may be used.  (+) Braces may be needed to insulate
       a variable substitution from a literal colon just as with History substitution (q.v.); any
       modifiers must appear within the braces.

       The following substitutions can not be modified with `:' modifiers.

       $?name
       ${?name}
               Substitutes the string `1' if name is set, `0' if it is not.
       $?0     Substitutes  `1' if the current input filename is known, `0' if it is not.  Always
               `0' in interactive shells.
       $#name
       ${#name}
               Substitutes the number of words in name.
       $#      Equivalent to `$#argv'.  (+)
       $%name
       ${%name}
               Substitutes the number of characters in name.  (+)
       $%number
       ${%number}
               Substitutes the number of characters in $argv[number].  (+)
       $?      Equivalent to `$status'.  (+)
       $$      Substitutes the (decimal) process number of the (parent) shell.
       $!      Substitutes the (decimal) process number of the last background process started by
               this shell.  (+)
       $_      Substitutes the command line of the last command executed.  (+)
       $<      Substitutes  a  line  from  the  standard  input,  with  no further interpretation
               thereafter.  It can be used to read from the keyboard  in  a  shell  script.   (+)
               While  csh  always  quotes  $<, as if it were equivalent to `$<:q', tcsh does not.
               Furthermore, when tcsh is waiting for a line to be typed  the  user  may  type  an
               interrupt  to interrupt the sequence into which the line is to be substituted, but
               csh does not allow this.

       The  editor  command  expand-variables,  normally  bound  to  `^X-$',  can  be   used   to
       interactively expand individual variables.

   Command, filename and directory stack substitution
       The  remaining substitutions are applied selectively to the arguments of builtin commands.
       This means that portions of expressions which are not evaluated are not subjected to these
       expansions.   For  commands  which  are  not  internal  to  the shell, the command name is
       substituted separately from the argument list.  This occurs very late, after  input-output
       redirection is performed, and in a child of the main shell.

   Command substitution
       Command  substitution  is  indicated by a command enclosed in ``'.  The output from such a
       command is broken into separate words at blanks, tabs and newlines,  and  null  words  are
       discarded.   The  output  is  variable  and  command  substituted  and put in place of the
       original string.

       Command substitutions inside double quotes (`"') retain blanks  and  tabs;  only  newlines
       force  new  words.  The single final newline does not force a new word in any case.  It is
       thus possible for a command substitution to yield only part of a word, even if the command
       outputs a complete line.

       By  default,  the  shell  since  version  6.12  replaces  all  newline and carriage return
       characters in the command by spaces.  If this is switched  off  by  unsetting  csubstnonl,
       newlines separate commands as usual.

   Filename substitution
       If a word contains any of the characters `*', `?', `[' or `{' or begins with the character
       `~' it is a candidate for filename substitution, also known as ``globbing''.  This word is
       then  regarded as a pattern (``glob-pattern''), and replaced with an alphabetically sorted
       list of file names which match the pattern.

       In matching filenames, the character `.' at the beginning of  a  filename  or  immediately
       following  a  `/',  as well as the character `/' must be matched explicitly (unless either
       globdot or globstar or both  are  set(+)).   The  character  `*'  matches  any  string  of
       characters,  including  the  null string.  The character `?' matches any single character.
       The sequence `[...]' matches any one of the characters enclosed.  Within `[...]',  a  pair
       of characters separated by `-' matches any character lexically between the two.

       (+)  Some glob-patterns can be negated: The sequence `[^...]' matches any single character
       not specified by the characters and/or ranges of characters in the braces.

       An entire glob-pattern can also be negated with `^':

           > echo *
           bang crash crunch ouch
           > echo ^cr*
           bang ouch

       Glob-patterns which do not use `?', `*', or `[]' or which use `{}' or `~' (below) are  not
       negated correctly.

       The  metanotation  `a{b,c,d}e'  is  a shorthand for `abe ace ade'.  Left-to-right order is
       preserved:    `/usr/source/s1/{oldls,ls}.c'     expands     to     `/usr/source/s1/oldls.c
       /usr/source/s1/ls.c'.   The  results  of  matches  are sorted separately at a low level to
       preserve this order: `../{memo,*box}' might expand to  `../memo  ../box  ../mbox'.   (Note
       that  `memo' was not sorted with the results of matching `*box'.)  It is not an error when
       this construct expands to files which do not exist, but it is possible  to  get  an  error
       from  a command to which the expanded list is passed.  This construct may be nested.  As a
       special case the words `{', `}' and `{}' are passed undisturbed.

       The character `~' at the beginning of a filename refers  to  home  directories.   Standing
       alone,  i.e., `~', it expands to the invoker's home directory as reflected in the value of
       the home shell variable.  When followed by a name consisting of letters,  digits  and  `-'
       characters  the  shell  searches  for  a  user  with  that name and substitutes their home
       directory; thus `~ken' might expand to `/usr/ken' and `~ken/chmach' to  `/usr/ken/chmach'.
       If  the  character  `~'  is  followed by a character other than a letter or `/' or appears
       elsewhere than at the beginning of a word, it is left undisturbed.  A command like `setenv
       MANPATH   /usr/man:/usr/local/man:~/lib/man'   does  not,  therefore,  do  home  directory
       substitution as one might hope.

       It is an error for a glob-pattern containing `*', `?', `[' or `~', with  or  without  `^',
       not to match any files.  However, only one pattern in a list of glob-patterns must match a
       file (so that, e.g., `rm *.a *.c *.o' would fail only  if  there  were  no  files  in  the
       current  directory  ending in `.a', `.c', or `.o'), and if the nonomatch shell variable is
       set a pattern (or list of patterns) which matches nothing is left  unchanged  rather  than
       causing an error.

       The  globstar shell variable can be set to allow `**' or `***' as a file glob pattern that
       matches any string of characters including `/', recursively traversing any  existing  sub-
       directories.   For  example, `ls **.c' will list all the .c files in the current directory
       tree.  If  used  by  itself,  it  will  match  zero  or  more  sub-directories  (e.g.  `ls
       /usr/include/**/time.h'  will  list  any file named `time.h' in the /usr/include directory
       tree; `ls /usr/include/**time.h' will match any file in the  /usr/include  directory  tree
       ending  in  `time.h';  and `ls /usr/include/**time**.h' will match any .h file with `time'
       either in a subdirectory name or in  the  filename  itself).   To  prevent  problems  with
       recursion,  the  `**'  glob-pattern  will  not  descend  into a symbolic link containing a
       directory.  To override this, use `***' (+)

       The noglob shell variable can be set to prevent filename substitution, and the expand-glob
       editor  command,  normally bound to `^X-*', can be used to interactively expand individual
       filename substitutions.

   Directory stack substitution (+)
       The directory stack is a list of directories, numbered from zero, used by the pushd,  popd
       and  dirs builtin commands (q.v.).  dirs can print, store in a file, restore and clear the
       directory stack at any time, and the savedirs and dirsfile shell variables can be  set  to
       store  the  directory stack automatically on logout and restore it on login.  The dirstack
       shell variable can be examined to see  the  directory  stack  and  set  to  put  arbitrary
       directories into the directory stack.

       The  character  `='  followed  by  one or more digits expands to an entry in the directory
       stack.  The special case `=-' expands to the last directory in the stack.  For example,

           > dirs -v
           0       /usr/bin
           1       /usr/spool/uucp
           2       /usr/accts/sys
           > echo =1
           /usr/spool/uucp
           > echo =0/calendar
           /usr/bin/calendar
           > echo =-
           /usr/accts/sys

       The noglob and nonomatch shell variables and  the  expand-glob  editor  command  apply  to
       directory stack as well as filename substitutions.

   Other substitutions (+)
       There  are  several  more transformations involving filenames, not strictly related to the
       above but mentioned here for completeness.  Any filename may be expanded to  a  full  path
       when  the  symlinks  variable (q.v.) is set to `expand'.  Quoting prevents this expansion,
       and the normalize-path editor command does it on  demand.   The  normalize-command  editor
       command  expands  commands  in  PATH  into  full  paths  on demand.  Finally, cd and pushd
       interpret `-' as the old working directory (equivalent to the shell variable  owd).   This
       is  not  a  substitution  at  all,  but an abbreviation recognized by only those commands.
       Nonetheless, it too can be prevented by quoting.

   Commands
       The next three sections describe how the shell executes  commands  and  deals  with  their
       input and output.

   Simple commands, pipelines and sequences
       A  simple  command  is a sequence of words, the first of which specifies the command to be
       executed.  A series of simple commands joined by `|' characters  forms  a  pipeline.   The
       output of each command in a pipeline is connected to the input of the next.

       Simple  commands and pipelines may be joined into sequences with `;', and will be executed
       sequentially.  Commands and pipelines can also be joined into sequences with `||' or `&&',
       indicating,  as  in  the  C  language, that the second is to be executed only if the first
       fails or succeeds respectively.

       A simple command, pipeline or sequence may be placed  in  parentheses,  `()',  to  form  a
       simple  command,  which  may in turn be a component of a pipeline or sequence.  A command,
       pipeline or sequence can be executed without waiting for it to terminate by  following  it
       with an `&'.

   Builtin and non-builtin command execution
       Builtin commands are executed within the shell.  If any component of a pipeline except the
       last is a builtin command, the pipeline is executed in a subshell.

       Parenthesized commands are always executed in a subshell.

           (cd; pwd); pwd

       thus prints the home directory, leaving you where you were (printing this after  the  home
       directory), while

           cd; pwd

       leaves  you  in the home directory.  Parenthesized commands are most often used to prevent
       cd from affecting the current shell.

       When a command to be executed is found not to be a builtin command the shell  attempts  to
       execute  the  command  via execve(2).  Each word in the variable path names a directory in
       which the shell will look for the command.  If the shell is not given  a  -f  option,  the
       shell  hashes the names in these directories into an internal table so that it will try an
       execve(2) in only a directory where there is a possibility that the command resides there.
       This greatly speeds command location when a large number of directories are present in the
       search path. This hashing mechanism is not used:

       1.  If hashing is turned explicitly off via unhash.

       2.  If the shell was given a -f argument.

       3.  For each directory component of path which does not begin with a `/'.

       4.  If the command contains a `/'.

       In the above four cases the shell concatenates each component of the path vector with  the
       given  command name to form a path name of a file which it then attempts to execute it. If
       execution is successful, the search stops.

       If the file has execute permissions but is not an executable to the system  (i.e.,  it  is
       neither  an  executable  binary  nor  a script that specifies its interpreter), then it is
       assumed to be a file containing shell commands and a new shell is spawned to read it.  The
       shell special alias may be set to specify an interpreter other than the shell itself.

       On systems which do not understand the `#!' script interpreter convention the shell may be
       compiled to emulate it; see the version shell variable.  If so, the shell checks the first
       line of the file to see if it is of the form `#!interpreter arg ...'.  If it is, the shell
       starts interpreter with the given args and feeds the file to it on standard input.

   Input/output
       The standard input and standard output of a command may be redirected with  the  following
       syntax:

       < name  Open  file  name  (which  is first variable, command and filename expanded) as the
               standard input.
       << word Read the shell input up to a line  which  is  identical  to  word.   word  is  not
               subjected  to  variable,  filename or command substitution, and each input line is
               compared to word before any substitutions are done on this input line.   Unless  a
               quoting  `\',  `"', `' or ``' appears in word variable and command substitution is
               performed on the intervening lines, allowing  `\'  to  quote  `$',  `\'  and  ``'.
               Commands  which  are  substituted  have  all blanks, tabs, and newlines preserved,
               except for the final newline which is dropped.  The resultant text is placed in an
               anonymous temporary file which is given to the command as standard input.
       > name
       >! name
       >& name
       >&! name
               The  file  name is used as standard output.  If the file does not exist then it is
               created; if the file exists, it is truncated, its previous contents being lost.

               If the shell variable noclobber is set, then the file  must  not  exist  or  be  a
               character  special  file  (e.g.,  a  terminal or `/dev/null') or an error results.
               This helps prevent accidental destruction of files.  In this case  the  `!'  forms
               can  be  used  to  suppress this check.  If notempty is given in noclobber, `>' is
               allowed on empty files; if ask is set, an interacive  confirmation  is  presented,
               rather than an error.

               The  forms  involving  `&'  route the diagnostic output into the specified file as
               well as the standard output.  name is expanded  in  the  same  way  as  `<'  input
               filenames are.
       >> name
       >>& name
       >>! name
       >>&! name
               Like  `>', but appends output to the end of name.  If the shell variable noclobber
               is set, then it is an error for the file not to exist, unless one of the `!' forms
               is given.

       A  command  receives  the  environment  in  which the shell was invoked as modified by the
       input-output parameters and the presence of the command in a pipeline.  Thus, unlike  some
       previous  shells, commands run from a file of shell commands have no access to the text of
       the commands by default; rather they receive the original standard  input  of  the  shell.
       The  `<<'  mechanism  should  be  used to present inline data.  This permits shell command
       scripts to function as components of pipelines and allows the  shell  to  block  read  its
       input.   Note  that the default standard input for a command run detached is not the empty
       file /dev/null, but the original standard input of the shell.  If this is a  terminal  and
       if  the  process  attempts  to read from the terminal, then the process will block and the
       user will be notified (see Jobs).

       Diagnostic output may be directed through a pipe with the standard output.  Simply use the
       form `|&' rather than just `|'.

       The  shell  cannot  presently redirect diagnostic output without also redirecting standard
       output, but `(command > output-file) >& error-file' is  often  an  acceptable  workaround.
       Either output-file or error-file may be `/dev/tty' to send output to the terminal.

   Features
       Having  described how the shell accepts, parses and executes command lines, we now turn to
       a variety of its useful features.

   Control flow
       The shell contains a number of commands which can be used to regulate the flow of  control
       in  command  files  (shell  scripts) and (in limited but useful ways) from terminal input.
       These commands all operate by forcing the shell to reread or skip in its input and, due to
       the implementation, restrict the placement of some of the commands.

       The  foreach,  switch,  and  while  statements, as well as the if-then-else form of the if
       statement, require that the major keywords appear in a single simple command on  an  input
       line as shown below.

       If  the shell's input is not seekable, the shell buffers up input whenever a loop is being
       read and performs seeks in this internal buffer to accomplish the rereading implied by the
       loop.   (To  the  extent  that  this  allows,  backward gotos will succeed on non-seekable
       inputs.)

   Expressions
       The if, while and exit builtin  commands  use  expressions  with  a  common  syntax.   The
       expressions  can  include any of the operators described in the next three sections.  Note
       that the @ builtin command (q.v.) has its own separate syntax.

   Logical, arithmetical and comparison operators
       These operators are similar to those of C and have the same precedence.  They include

           ||  &&  |  ^  &  ==  !=  =~  !~  <=  >=
           <  > <<  >>  +  -  *  /  %  !  ~  (  )

       Here the precedence increases to the right, `==' `!=' `=~' and `!~',  `<='  `>='  `<'  and
       `>', `<<' and `>>', `+' and `-', `*' `/' and `%' being, in groups, at the same level.  The
       `==' `!=' `=~' and `!~' operators compare their arguments as strings; all  others  operate
       on numbers.  The operators `=~' and `!~' are like `!=' and `==' except that the right hand
       side is a glob-pattern (see Filename substitution) against which the left hand operand  is
       matched.   This  reduces  the  need for use of the switch builtin command in shell scripts
       when all that is really needed is pattern matching.

       Null or missing arguments are considered `0'.  The results of all expressions are strings,
       which  represent  decimal  numbers.   It is important to note that no two components of an
       expression can appear in the same word; except when adjacent to components of  expressions
       which are syntactically significant to the parser (`&' `|' `<' `>' `(' `)') they should be
       surrounded by spaces.

   Command exit status
       Commands can be executed in expressions and their exit status returned by  enclosing  them
       in  braces  (`{}').   Remember  that  the braces should be separated from the words of the
       command by spaces.  Command executions succeed, returning true, i.e., `1', if the  command
       exits  with  status  0, otherwise they fail, returning false, i.e., `0'.  If more detailed
       status information is  required  then  the  command  should  be  executed  outside  of  an
       expression and the status shell variable examined.

   File inquiry operators
       Some  of  these operators perform true/false tests on files and related objects.  They are
       of the form -op file, where op is one of

           r   Read access
           w   Write access
           x   Execute access
           X   Executable in the path or shell builtin, e.g., `-X ls' and `-X ls-F' are generally
               true, but `-X /bin/ls' is not (+)
           e   Existence
           o   Ownership
           z   Zero size
           s   Non-zero size (+)
           f   Plain file
           d   Directory
           l   Symbolic link (+) *
           b   Block special file (+)
           c   Character special file (+)
           p   Named pipe (fifo) (+) *
           S   Socket special file (+) *
           u   Set-user-ID bit is set (+)
           g   Set-group-ID bit is set (+)
           k   Sticky bit is set (+)
           t   file (which must be a digit) is an open file descriptor for a terminal device (+)
           R   Has been migrated (Convex only) (+)
           L   Applies subsequent operators in a multiple-operator test to a symbolic link rather
               than to the file to which the link points (+) *

       file is command and filename expanded and then tested to  see  if  it  has  the  specified
       relationship  to  the  real  user.   If file does not exist or is inaccessible or, for the
       operators indicated by `*', if the specified file type  does  not  exist  on  the  current
       system, then all inquiries return false, i.e., `0'.

       These  operators  may be combined for conciseness: `-xy file' is equivalent to `-x file &&
       -y file'.  (+) For example, `-fx' is true (returns `1') for plain  executable  files,  but
       not for directories.

       L may be used in a multiple-operator test to apply subsequent operators to a symbolic link
       rather than to the file to which the link points.  For example, `-lLo' is true  for  links
       owned  by  the  invoking user.  Lr, Lw and Lx are always true for links and false for non-
       links.  L has a different meaning when it is the  last  operator  in  a  multiple-operator
       test; see below.

       It is possible but not useful, and sometimes misleading, to combine operators which expect
       file to be a file with operators which do not (e.g., X and t).  Following L  with  a  non-
       file operator can lead to particularly strange results.

       Other  operators  return  other information, i.e., not just `0' or `1'.  (+) They have the
       same format as before; op may be one of

           A       Last file access time, as the number of seconds since the epoch
           A:      Like A, but in timestamp format, e.g., `Fri May 14 16:36:10 1993'
           M       Last file modification time
           M:      Like M, but in timestamp format
           C       Last inode modification time
           C:      Like C, but in timestamp format
           D       Device number
           I       Inode number
           F       Composite file identifier, in the form device:inode
           L       The name of the file pointed to by a symbolic link
           N       Number of (hard) links
           P       Permissions, in octal, without leading zero
           P:      Like P, with leading zero
           Pmode   Equivalent to `-P file & mode', e.g., `-P22 file'  returns  `22'  if  file  is
                   writable by group and other, `20' if by group only, and `0' if by neither
           Pmode:  Like Pmode, with leading zero
           U       Numeric userid
           U:      Username, or the numeric userid if the username is unknown
           G       Numeric groupid
           G:      Groupname, or the numeric groupid if the groupname is unknown
           Z       Size, in bytes

       Only  one  of  these  operators may appear in a multiple-operator test, and it must be the
       last.  Note that L has a different meaning at the end of  and  elsewhere  in  a  multiple-
       operator  test.   Because `0' is a valid return value for many of these operators, they do
       not return `0' when they fail: most return `-1', and F returns `:'.

       If the shell is compiled with POSIX defined (see the version shell variable),  the  result
       of a file inquiry is based on the permission bits of the file and not on the result of the
       access(2) system call.  For example, if one tests a file with -w whose  permissions  would
       ordinarily  allow  writing  but which is on a file system mounted read-only, the test will
       succeed in a POSIX shell but fail in a non-POSIX shell.

       File inquiry operators can also be evaluated with the filetest builtin command (q.v.) (+).

   Jobs
       The shell associates a job with each pipeline.  It keeps a table of current jobs,  printed
       by  the  jobs  command,  and  assigns  them  small integer numbers.  When a job is started
       asynchronously with `&', the shell prints a line which looks like

           [1] 1234

       indicating that the job which was started asynchronously was job  number  1  and  had  one
       (top-level) process, whose process id was 1234.

       If  you  are  running  a  job  and  wish  to do something else you may hit the suspend key
       (usually `^Z'), which sends a STOP signal  to  the  current  job.   The  shell  will  then
       normally  indicate  that  the  job  has been `Suspended' and print another prompt.  If the
       listjobs shell variable is set, all jobs will be listed like the jobs builtin command;  if
       it  is  set  to  `long'  the listing will be in long format, like `jobs -l'.  You can then
       manipulate the state of the suspended job.  You can put it in the ``background'' with  the
       bg  command  or  run  some  other  commands  and  eventually  bring  the job back into the
       ``foreground'' with fg.  (See also the run-fg-editor editor command.)  A `^Z' takes effect
       immediately and is like an interrupt in that pending output and unread input are discarded
       when it is typed.  The wait builtin command causes the shell to wait  for  all  background
       jobs to complete.

       The `^]' key sends a delayed suspend signal, which does not generate a STOP signal until a
       program attempts to read(2) it, to the current job.  This can usefully be typed ahead when
       you  have  prepared some commands for a job which you wish to stop after it has read them.
       The `^Y' key performs this function in csh(1); in tcsh, `^Y' is an editing command.  (+)

       A job being run in the background stops if it tries to read from the terminal.  Background
       jobs  are  normally  allowed  to  produce  output,  but this can be disabled by giving the
       command `stty tostop'.  If you set this tty option, then background jobs  will  stop  when
       they try to produce output like they do when they try to read input.

       There  are several ways to refer to jobs in the shell.  The character `%' introduces a job
       name.  If you wish to refer to job number 1, you can name it as `%1'.  Just naming  a  job
       brings  it to the foreground; thus `%1' is a synonym for `fg %1', bringing job 1 back into
       the foreground.  Similarly, saying `%1 &' resumes job 1 in the background, just  like  `bg
       %1'.  A job can also be named by an unambiguous prefix of the string typed in to start it:
       `%ex' would normally restart a suspended ex(1) job, if there were only one  suspended  job
       whose name began with the string `ex'.  It is also possible to say `%?string' to specify a
       job whose text contains string, if there is only one such job.

       The shell maintains a notion of the current and previous jobs.  In  output  pertaining  to
       jobs,  the  current  job  is  marked  with  a  `+'  and  the previous job with a `-'.  The
       abbreviations `%+', `%', and (by analogy with the syntax of the  history  mechanism)  `%%'
       all refer to the current job, and `%-' refers to the previous job.

       The  job  control mechanism requires that the stty(1) option `new' be set on some systems.
       It is an artifact from a `new' implementation of the tty driver which allows generation of
       interrupt  characters  from  the keyboard to tell jobs to stop.  See stty(1) and the setty
       builtin command for details on setting options in the new tty driver.

   Status reporting
       The shell learns immediately whenever a process changes state.  It  normally  informs  you
       whenever  a  job  becomes  blocked so that no further progress is possible, but only right
       before it prints a prompt.  This is done so that it does not otherwise disturb your  work.
       If,  however,  you set the shell variable notify, the shell will notify you immediately of
       changes of status in background jobs.  There is also a shell command notify which marks  a
       single process so that its status changes will be immediately reported.  By default notify
       marks the current process; simply say `notify' after starting a background job to mark it.

       When you try to leave the shell while jobs are stopped, you will be warned that `There are
       suspended  jobs.'  You  may  use the jobs command to see what they are.  If you do this or
       immediately try to exit again, the shell  will  not  warn  you  a  second  time,  and  the
       suspended jobs will be terminated.

   Automatic, periodic and timed events (+)
       There  are  various  ways  to run commands and take other actions automatically at various
       times in the ``life cycle'' of the shell.  They are  summarized  here,  and  described  in
       detail  under  the  appropriate  Builtin  commands,  Special  shell  variables and Special
       aliases.

       The sched builtin command puts commands in a scheduled-event list, to be executed  by  the
       shell at a given time.

       The  beepcmd,  cwdcmd,  periodic,  precmd, postcmd, and jobcmd Special aliases can be set,
       respectively, to execute commands when the shell wants to ring the bell, when the  working
       directory  changes,  every  tperiod  minutes, before each prompt, before each command gets
       executed, after each command gets executed, and when a job is started or is  brought  into
       the foreground.

       The autologout shell variable can be set to log out or lock the shell after a given number
       of minutes of inactivity.

       The mail shell variable can be set to check for new mail periodically.

       The printexitvalue shell variable can be set to print the exit status  of  commands  which
       exit with a status other than zero.

       The  rmstar  shell  variable  can be set to ask the user, when `rm *' is typed, if that is
       really what was meant.

       The time shell variable can  be  set  to  execute  the  time  builtin  command  after  the
       completion of any process that takes more than a given number of CPU seconds.

       The  watch and who shell variables can be set to report when selected users log in or out,
       and the log builtin command reports on those users at any time.

   Native Language System support (+)
       The shell is eight bit clean (if so compiled; see the version  shell  variable)  and  thus
       supports character sets needing this capability.  NLS support differs depending on whether
       or not the shell was compiled to use the system's NLS (again,  see  version).   In  either
       case,  7-bit  ASCII  is  the  default  character  code  (e.g., the classification of which
       characters are printable) and sorting, and  changing  the  LANG  or  LC_CTYPE  environment
       variables causes a check for possible changes in these respects.

       When  using the system's NLS, the setlocale(3) function is called to determine appropriate
       character code/classification and sorting (e.g., a 'en_CA.UTF-8' would yield "UTF-8" as  a
       character  code).   This  function  typically  examines  the LANG and LC_CTYPE environment
       variables; refer to the system documentation for further  details.   When  not  using  the
       system's NLS, the shell simulates it by assuming that the ISO 8859-1 character set is used
       whenever either of the LANG and LC_CTYPE variables are set, regardless  of  their  values.
       Sorting is not affected for the simulated NLS.

       In  addition,  with  both  real  and  simulated NLS, all printable characters in the range
       \200-\377, i.e., those that have M-char  bindings,  are  automatically  rebound  to  self-
       insert-command.   The  corresponding binding for the escape-char sequence, if any, is left
       alone.  These characters are not rebound if the  NOREBIND  environment  variable  is  set.
       This  may  be  useful for the simulated NLS or a primitive real NLS which assumes full ISO
       8859-1.  Otherwise, all M-char bindings in the range  \240-\377  are  effectively  undone.
       Explicitly rebinding the relevant keys with bindkey is of course still possible.

       Unknown  characters  (i.e.,  those  that are neither printable nor control characters) are
       printed in the format \nnn.  If the tty is not in 8 bit mode, other 8 bit  characters  are
       printed  by converting them to ASCII and using standout mode.  The shell never changes the
       7/8 bit mode of the tty and tracks user-initiated changes of 7/8 bit mode.  NLS users (or,
       for that matter, those who want to use a meta key) may need to explicitly set the tty in 8
       bit mode through the appropriate stty(1) command in, e.g., the ~/.login file.

   OS variant support (+)
       A number of new builtin commands are provided to support features in particular  operating
       systems.  All are described in detail in the Builtin commands section.

       On  systems  that support TCF (aix-ibm370, aix-ps2), getspath and setspath get and set the
       system execution path, getxvers and setxvers get and set the experimental  version  prefix
       and  migrate  migrates processes between sites.  The jobs builtin prints the site on which
       each job is executing.

       Under BS2000, bs2cmd executes commands of the underlying BS2000/OSD operating system.

       Under Domain/OS, inlib adds shared libraries to the current environment, rootnode  changes
       the rootnode and ver changes the systype.

       Under Mach, setpath is equivalent to Mach's setpath(1).

       Under Masscomp/RTU and Harris CX/UX, universe sets the universe.

       Under Harris CX/UX, ucb or att runs a command under the specified universe.

       Under Convex/OS, warp prints or sets the universe.

       The  VENDOR,  OSTYPE  and MACHTYPE environment variables indicate respectively the vendor,
       operating system and machine type (microprocessor class or machine model) of the system on
       which  the  shell  thinks it is running.  These are particularly useful when sharing one's
       home directory between several types of machines; one can, for example,

           set path = (~/bin.$MACHTYPE /usr/ucb /bin /usr/bin .)

       in one's ~/.login and put  executables  compiled  for  each  machine  in  the  appropriate
       directory.

       The version shell variable indicates what options were chosen when the shell was compiled.

       Note  also  the newgrp builtin, the afsuser and echo_style shell variables and the system-
       dependent locations of the shell's input files (see FILES).

   Signal handling
       Login shells ignore interrupts when reading the file ~/.logout.  The  shell  ignores  quit
       signals  unless  started  with -q.  Login shells catch the terminate signal, but non-login
       shells inherit the terminate behavior from their parents.  Other signals have  the  values
       which the shell inherited from its parent.

       In  shell  scripts,  the  shell's  handling  of  interrupt  and  terminate  signals can be
       controlled with onintr, and its handling of hangups can be controlled with hup and nohup.

       The shell exits on a hangup (see also the logout shell variable).  By default, the shell's
       children  do  too,  but the shell does not send them a hangup when it exits.  hup arranges
       for the shell to send a hangup to a child when it exits, and nohup sets a child to  ignore
       hangups.

   Terminal management (+)
       The  shell  uses  three  different  sets  of  terminal  (``tty'') modes: `edit', used when
       editing, `quote', used when quoting literal characters, and `execute', used when executing
       commands.   The  shell  holds some settings in each mode constant, so commands which leave
       the tty in a confused state do not interfere with  the  shell.   The  shell  also  matches
       changes in the speed and padding of the tty.  The list of tty modes that are kept constant
       can be examined and modified with the setty builtin.  Note that although the  editor  uses
       CBREAK mode (or its equivalent), it takes typed-ahead characters anyway.

       The  echotc,  settc  and  telltc  commands  can  be  used to manipulate and debug terminal
       capabilities from the command line.

       On systems that support SIGWINCH  or  SIGWINDOW,  the  shell  adapts  to  window  resizing
       automatically  and  adjusts  the  environment  variables LINES and COLUMNS if set.  If the
       environment variable TERMCAP contains li# and  co#  fields,  the  shell  adjusts  them  to
       reflect the new window size.

REFERENCE

       The  next  sections of this manual describe all of the available Builtin commands, Special
       aliases and Special shell variables.

   Builtin commands
       %job    A synonym for the fg builtin command.

       %job &  A synonym for the bg builtin command.

       :       Does nothing, successfully.

       @
       @ name = expr
       @ name[index] = expr
       @ name++|--
       @ name[index]++|--
               The first form prints the values of all shell variables.

               The second form assigns the value of expr to name.  The  third  form  assigns  the
               value  of  expr  to  the  index'th  component  of name; both name and its index'th
               component must already exist.

               expr may contain the operators `*', `+', etc., as in C.   If  expr  contains  `<',
               `>',  `&'  or `' then at least that part of expr must be placed within `()'.  Note
               that the syntax of expr has nothing to do with that described under Expressions.

               The fourth and fifth forms increment  (`++')  or  decrement  (`--')  name  or  its
               index'th component.

               The  space  between `@' and name is required.  The spaces between name and `=' and
               between `=' and expr are optional.   Components  of  expr  must  be  separated  by
               spaces.

       alias [name [wordlist]]
               Without  arguments,  prints  all  aliases.   With name, prints the alias for name.
               With name and wordlist, assigns wordlist  as  the  alias  of  name.   wordlist  is
               command and filename substituted.  name may not be `alias' or `unalias'.  See also
               the unalias builtin command.

       alloc   Shows the amount of dynamic memory  acquired,  broken  down  into  used  and  free
               memory.   With  an  argument shows the number of free and used blocks in each size
               category.  The categories start at size 8 and double at each step.  This command's
               output  may vary across system types, because systems other than the VAX may use a
               different memory allocator.

       bg [%job ...]
               Puts the specified  jobs  (or,  without  arguments,  the  current  job)  into  the
               background,  continuing each if it is stopped.  job may be a number, a string, `',
               `%', `+' or `-' as described under Jobs.

       bindkey [-l|-d|-e|-v|-u] (+)
       bindkey [-a] [-b] [-k] [-r] [--] key (+)
       bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)
               Without options, the first form lists all bound keys and  the  editor  command  to
               which  each  is  bound,  the  second form lists the editor command to which key is
               bound and the third form  binds  the  editor  command  command  to  key.   Options
               include:

               -l  Lists all editor commands and a short description of each.
               -d  Binds  all keys to the standard bindings for the default editor, as per -e and
                   -v below.
               -e  Binds all keys to emacs(1)-style bindings.  Unsets vimode.
               -v  Binds all keys to vi(1)-style bindings.  Sets vimode.
               -a  Lists or changes key-bindings in the alternative key map.  This is the key map
                   used in vimode command mode.
               -b  key  is  interpreted as a control character written ^character (e.g., `^A') or
                   C-character (e.g., `C-A'), a meta character written M-character (e.g., `M-A'),
                   a  function key written F-string (e.g., `F-string'), or an extended prefix key
                   written X-character (e.g., `X-A').
               -k  key is interpreted as a symbolic arrow key name, which may be one  of  `down',
                   `up', `left' or `right'.
               -r  Removes  key's  binding.   Be careful: `bindkey -r' does not bind key to self-
                   insert-command (q.v.), it unbinds key completely.
               -c  command is interpreted as a builtin or external command instead of  an  editor
                   command.
               -s  command is taken as a literal string and treated as terminal input when key is
                   typed.  Bound keys in command are themselves reinterpreted, and this continues
                   for ten levels of interpretation.
               --  Forces  a  break from option processing, so the next word is taken as key even
                   if it begins with '-'.
               -u (or any invalid option)
                   Prints a usage message.

               key may be a single character or a string.  If a command is bound to a string, the
               first  character  of the string is bound to sequence-lead-in and the entire string
               is bound to the command.

               Control characters in key can be literal (they can be typed by preceding them with
               the  editor  command  quoted-insert,  normally  bound  to  `^V') or written caret-
               character style, e.g., `^A'.  Delete is written `^?'  (caret-question mark).   key
               and  command  can  contain  backslashed escape sequences (in the style of System V
               echo(1)) as follows:

                   \a      Bell
                   \b      Backspace
                   \e      Escape
                   \f      Form feed
                   \n      Newline
                   \r      Carriage return
                   \t      Horizontal tab
                   \v      Vertical tab
                   \nnn    The ASCII character corresponding to the octal number nnn

               `\' nullifies the special meaning of the  following  character,  if  it  has  any,
               notably `\' and `^'.

       bs2cmd bs2000-command (+)
               Passes  bs2000-command  to the BS2000 command interpreter for execution. Only non-
               interactive commands can be executed, and  it  is  not  possible  to  execute  any
               command  that  would  overlay  the  image of the current process, like /EXECUTE or
               /CALL-PROCEDURE. (BS2000 only)

       break   Causes execution to resume after the end  of  the  nearest  enclosing  foreach  or
               while.   The  remaining  commands  on  the current line are executed.  Multi-level
               breaks are thus possible by writing them all on one line.

       breaksw Causes a break from a switch, resuming after the endsw.

       builtins (+)
               Prints the names of all builtin commands.

       bye (+) A synonym for the logout builtin command.  Available only  if  the  shell  was  so
               compiled; see the version shell variable.

       case label:
               A label in a switch statement as discussed below.

       cd [-p] [-l] [-n|-v] [I--] [name]
               If  a  directory name is given, changes the shell's working directory to name.  If
               not, changes to home, unless the cdtohome variable is not set,  in  which  case  a
               name  is  required.   If  name  is  `-'  it is interpreted as the previous working
               directory (see Other substitutions).  (+) If name is not  a  subdirectory  of  the
               current  directory (and does not begin with `/', `./' or `../'), each component of
               the variable cdpath is checked to see if it has a subdirectory name.  Finally,  if
               all  else  fails  but name is a shell variable whose value begins with `/' or '.',
               then this is tried to see if it is a directory, and the -p option is implied.

               With -p, prints the final directory stack, just like dirs.   The  -l,  -n  and  -v
               flags  have  the  same  effect  on cd as on dirs, and they imply -p.  (+) Using --
               forces a break from option processing so the next word is taken as  the  directory
               name even if it begins with '-'. (+)

               See also the implicitcd and cdtohome shell variables.

       chdir   A synonym for the cd builtin command.

       complete [command [word/pattern/list[:select]/[[suffix]/] ...]] (+)
               Without  arguments,  lists  all  completions.  With command, lists completions for
               command.  With command and word etc., defines completions.

               command may be a full command name or a glob-pattern (see Filename  substitution).
               It can begin with `-' to indicate that completion should be used only when command
               is ambiguous.

               word specifies which word relative to the current word is to be completed, and may
               be one of the following:

                   c   Current-word  completion.   pattern is a glob-pattern which must match the
                       beginning of the current word on the command  line.   pattern  is  ignored
                       when completing the current word.
                   C   Like c, but includes pattern when completing the current word.
                   n   Next-word  completion.   pattern  is  a  glob-pattern which must match the
                       beginning of the previous word on the command line.
                   N   Like n, but must match the beginning of the word two  before  the  current
                       word.
                   p   Position-dependent  completion.  pattern is a numeric range, with the same
                       syntax used to index shell variables, which must include the current word.

               list, the list of possible completions, may be one of the following:

                   a       Aliases
                   b       Bindings (editor commands)
                   c       Commands (builtin or external commands)
                   C       External commands which begin with the supplied path prefix
                   d       Directories
                   D       Directories which begin with the supplied path prefix
                   e       Environment variables
                   f       Filenames
                   F       Filenames which begin with the supplied path prefix
                   g       Groupnames
                   j       Jobs
                   l       Limits
                   n       Nothing
                   s       Shell variables
                   S       Signals
                   t       Plain (``text'') files
                   T       Plain (``text'') files which begin with the supplied path prefix
                   v       Any variables
                   u       Usernames
                   x       Like n, but prints select when list-choices is used.
                   X       Completions
                   $var    Words from the variable var
                   (...)   Words from the given list
                   `...`   Words from the output of command

               select is an optional glob-pattern.  If given, words from  only  list  that  match
               select  are  considered and the fignore shell variable is ignored.  The last three
               types of completion may not have a  select  pattern,  and  x  uses  select  as  an
               explanatory message when the list-choices editor command is used.

               suffix  is a single character to be appended to a successful completion.  If null,
               no character is appended.  If omitted (in which case the fourth delimiter can also
               be omitted), a slash is appended to directories and a space to other words.

               command  invoked  from  `...` version has additional environment variable set, the
               variable name is COMMAND_LINE and contains (as its name indicates) contents of the
               current  (already  typed in) command line. One can examine and use contents of the
               COMMAND_LINE variable in her custom script to build more sophisticated completions
               (see completion for svn(1) included in this package).

               Now  for  some  examples.   Some  commands  take only directories as arguments, so
               there's no point completing plain files.

                   > complete cd 'p/1/d/'

               completes only the first word following `cd' (`p/1')  with  a  directory.   p-type
               completion can also be used to narrow down command completion:

                   > co[^D]
                   complete compress
                   > complete -co* 'p/0/(compress)/'
                   > co[^D]
                   > compress

               This  completion  completes commands (words in position 0, `p/0') which begin with
               `co' (thus matching `co*') to `compress' (the only word in the list).  The leading
               `-' indicates that this completion is to be used with only ambiguous commands.

                   > complete find 'n/-user/u/'

               is  an  example  of  n-type completion.  Any word following `find' and immediately
               following `-user' is completed from the list of users.

                   > complete cc 'c/-I/d/'

               demonstrates c-type completion.  Any word following `cc' and beginning  with  `-I'
               is  completed  as a directory.  `-I' is not taken as part of the directory because
               we used lowercase c.

               Different lists are useful with different commands.

                   > complete alias 'p/1/a/'
                   > complete man 'p/*/c/'
                   > complete set 'p/1/s/'
                   > complete true 'p/1/x:Truth has no options./'

               These complete words following `alias' with  aliases,  `man'  with  commands,  and
               `set'  with  shell  variables.  `true' doesn't have any options, so x does nothing
               when completion is attempted and prints `Truth has no  options.'  when  completion
               choices are listed.

               Note  that  the  man example, and several other examples below, could just as well
               have used 'c/*' or 'n/*' as 'p/*'.

               Words can be completed from a variable evaluated at completion time,

                   > complete ftp 'p/1/$hostnames/'
                   > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu)
                   > ftp [^D]
                   rtfm.mit.edu tesla.ee.cornell.edu
                   > ftp [^C]
                   > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu uunet.uu.net)
                   > ftp [^D]
                   rtfm.mit.edu tesla.ee.cornell.edu uunet.uu.net

               or from a command run at completion time:

                   > complete kill 'p/*/`ps | awk \{print\ \$1\}`/'
                   > kill -9 [^D]
                   23113 23377 23380 23406 23429 23529 23530 PID

               Note that the complete command does not itself quote its arguments, so the braces,
               space and `$' in `{print $1}' must be quoted explicitly.

               One command can have multiple completions:

                   > complete dbx 'p/2/(core)/' 'p/*/c/'

               completes  the  second  argument  to  `dbx'  with  the  word  `core' and all other
               arguments with commands.  Note that the positional completion is specified  before
               the  next-word  completion.  Because completions are evaluated from left to right,
               if the next-word completion were specified first it would  always  match  and  the
               positional  completion  would  never  be  executed.  This is a common mistake when
               defining a completion.

               The select pattern is useful when a command takes files with only particular forms
               as arguments.  For example,

                   > complete cc 'p/*/f:*.[cao]/'

               completes  `cc' arguments to files ending in only `.c', `.a', or `.o'.  select can
               also exclude files, using negation of a glob-pattern as described  under  Filename
               substitution.  One might use

                   > complete rm 'p/*/f:^*.{c,h,cc,C,tex,1,man,l,y}/'

               to  exclude precious source code from `rm' completion.  Of course, one could still
               type excluded names manually  or  override  the  completion  mechanism  using  the
               complete-word-raw or list-choices-raw editor commands (q.v.).

               The  `C',  `D', `F' and `T' lists are like `c', `d', `f' and `t' respectively, but
               they use the select argument in a different way: to restrict completion  to  files
               beginning  with  a particular path prefix.  For example, the Elm mail program uses
               `=' as an abbreviation for one's mail directory.  One might use

                   > complete elm c@=@F:$HOME/Mail/@

               to complete `elm -f =' as if it were `elm -f ~/Mail/'.   Note  that  we  used  `@'
               instead  of  `/'  to avoid confusion with the select argument, and we used `$HOME'
               instead of `~' because home directory substitution works at only the beginning  of
               a word.

               suffix  is  used to add a nonstandard suffix (not space or `/' for directories) to
               completed words.

                   > complete finger 'c/*@/$hostnames/' 'p/1/u/@'

               completes arguments to `finger' from the list of users, appends an `@',  and  then
               completes  after  the  `@' from the `hostnames' variable.  Note again the order in
               which the completions are specified.

               Finally, here's a complex example for inspiration:

                   > complete find \
                   'n/-name/f/' 'n/-newer/f/' 'n/-{,n}cpio/f/' \
                   ´n/-exec/c/' 'n/-ok/c/' 'n/-user/u/' \
                   'n/-group/g/' 'n/-fstype/(nfs 4.2)/' \
                   'n/-type/(b c d f l p s)/' \
                   ´c/-/(name newer cpio ncpio exec ok user \
                   group fstype type atime ctime depth inum \
                   ls mtime nogroup nouser perm print prune \
                   size xdev)/' \
                   'p/*/d/'

               This completes words following `-name', `-newer', `-cpio'  or  `ncpio'  (note  the
               pattern  which  matches  both)  to  files,  words  following  `-exec'  or `-ok' to
               commands, words following `user' and `group' to users and groups respectively  and
               words  following  `-fstype'  or  `-type'  to  members of the given lists.  It also
               completes the switches themselves from the given list  (note  the  use  of  c-type
               completion) and completes anything not otherwise completed to a directory.  Whew.

               Remember  that programmed completions are ignored if the word being completed is a
               tilde substitution (beginning with `~') or a variable (beginning with  `$').   See
               also the uncomplete builtin command.

       continue
               Continues  execution  of  the nearest enclosing while or foreach.  The rest of the
               commands on the current line are executed.

       default:
               Labels the default case in a switch statement.  It  should  come  after  all  case
               labels.

       dirs [-l] [-n|-v]
       dirs -S|-L [filename] (+)
       dirs -c (+)
               The  first  form  prints the directory stack.  The top of the stack is at the left
               and the first directory in the stack is the current directory.  With  -l,  `~'  or
               `~name'  in  the output is expanded explicitly to home or the pathname of the home
               directory for user name.  (+) With -n, entries are wrapped before they  reach  the
               edge  of  the  screen.  (+) With -v, entries are printed one per line, preceded by
               their stack positions.  (+) If more than one of  -n  or  -v  is  given,  -v  takes
               precedence.  -p is accepted but does nothing.

               With  -S,  the second form saves the directory stack to filename as a series of cd
               and pushd commands.  With -L, the shell sources filename, which  is  presumably  a
               directory  stack file saved by the -S option or the savedirs mechanism.  In either
               case, dirsfile is used if filename is not given and ~/.cshdirs is used if dirsfile
               is unset.

               Note  that login shells do the equivalent of `dirs -L' on startup and, if savedirs
               is set, `dirs -S' before exiting.  Because  only  ~/.tcshrc  is  normally  sourced
               before ~/.cshdirs, dirsfile should be set in ~/.tcshrc rather than ~/.login.

               The last form clears the directory stack.

       echo [-n] word ...
               Writes  each  word  to  the  shell's  standard  output,  separated  by  spaces and
               terminated with a newline.  The echo_style shell variable may be  set  to  emulate
               (or  not)  the  flags  and escape sequences of the BSD and/or System V versions of
               echo; see echo(1).

       echotc [-sv] arg ... (+)
               Exercises the terminal  capabilities  (see  termcap(5))  in  args.   For  example,
               'echotc  home' sends the cursor to the home position, 'echotc cm 3 10' sends it to
               column 3 and row 10, and 'echotc ts 0; echo "This is a test."; echotc  fs'  prints
               "This is a test."  in the status line.

               If  arg  is  'baud',  'cols',  'lines', 'meta' or 'tabs', prints the value of that
               capability ("yes" or "no" indicating that the terminal does or does not have  that
               capability).   One  might  use  this  to  make the output from a shell script less
               verbose on slow terminals, or limit command output to the number of lines  on  the
               screen:

                   > set history=`echotc lines`

                   > @ history--
               Termcap  strings  may contain wildcards which will not echo correctly.  One should
               use double quotes when setting a shell variable to a terminal  capability  string,
               as in the following example that places the date in the status line:

                   > set tosl="`echotc ts 0`"
                   > set frsl="`echotc fs`"
                   > echo -n "$tosl";date; echo -n "$frsl"

               With  -s,  nonexistent capabilities return the empty string rather than causing an
               error.  With -v, messages are verbose.

       else
       end
       endif
       endsw   See the description of the foreach, if, switch, and while statements below.

       eval arg ...
               Treats the arguments as input to the shell and executes the  resulting  command(s)
               in  the  context  of  the current shell.  This is usually used to execute commands
               generated as the result of  command  or  variable  substitution,  because  parsing
               occurs before these substitutions.  See tset(1) for a sample use of eval.

       exec command
               Executes the specified command in place of the current shell.

       exit [expr]
               The  shell  exits  either  with the value of the specified expr (an expression, as
               described under Expressions) or, without expr, with the value 0.

       fg [%job ...]
               Brings the specified jobs (or,  without  arguments,  the  current  job)  into  the
               foreground,  continuing each if it is stopped.  job may be a number, a string, `',
               `%', `+' or `-' as described  under  Jobs.   See  also  the  run-fg-editor  editor
               command.

       filetest -op file ... (+)
               Applies  op  (which  is  a  file  inquiry operator as described under File inquiry
               operators) to each file and returns the results as a space-separated list.

       foreach name (wordlist)
       ...
       end     Successively sets the variable name to each member of wordlist  and  executes  the
               sequence of commands between this command and the matching end.  (Both foreach and
               end must appear alone on separate lines.)  The builtin  command  continue  may  be
               used  to  continue the loop prematurely and the builtin command break to terminate
               it prematurely.  When this command is read from the terminal,  the  loop  is  read
               once prompting with `foreach? ' (or prompt2) before any statements in the loop are
               executed.  If you make a mistake typing in a loop at the terminal you can  rub  it
               out.

       getspath (+)
               Prints the system execution path.  (TCF only)

       getxvers (+)
               Prints the experimental version prefix.  (TCF only)

       glob wordlist
               Like  echo,  but  the  `-n' parameter is not recognized and words are delimited by
               null characters in the output.  Useful for programs which wish to use the shell to
               filename expand a list of words.

       goto word
               word  is  filename  and command-substituted to yield a string of the form `label'.
               The shell rewinds its input as much as possible, searches for a line of  the  form
               `label:',  possibly preceded by blanks or tabs, and continues execution after that
               line.

       hashstat
               Prints a statistics line indicating how effective the internal hash table has been
               at  locating  commands  (and  avoiding  exec's).   An  exec  is attempted for each
               component of the path where the hash function indicates a  possible  hit,  and  in
               each component which does not begin with a `/'.

               On machines without vfork(2), prints only the number and size of hash buckets.

       history [-hTr] [n]
       history -S|-L|-M [filename] (+)
       history -c (+)
               The  first  form  prints  the  history  event list.  If n is given only the n most
               recent events are printed or saved.  With -h, the history list is printed  without
               leading numbers.  If -T is specified, timestamps are printed also in comment form.
               (This can be used to produce files suitable  for  loading  with  'history  -L'  or
               'source  -h'.)   With  -r,  the order of printing is most recent first rather than
               oldest first.

               With -S, the second form saves the history list to filename.  If the first word of
               the savehist shell variable is set to a number, at most that many lines are saved.
               If the second word of savehist is set to `merge', the history list is merged  with
               the  existing history file instead of replacing it (if there is one) and sorted by
               time stamp.  (+) Merging is intended for an environment like the X  Window  System
               with  several  shells  in  simultaneous  use.   If  the second word of savehist is
               `merge' and the third word is set to `lock',  the  history  file  update  will  be
               serialized  with other shell sessions that would possibly like to merge history at
               exactly the same time.

               With -L, the shell appends filename, which is presumably a history list  saved  by
               the  -S option or the savehist mechanism, to the history list.  -M is like -L, but
               the contents of filename are merged into the history list and sorted by timestamp.
               In  either  case, histfile is used if filename is not given and ~/.history is used
               if histfile is unset.  `history -L' is exactly like 'source  -h'  except  that  it
               does not require a filename.

               Note  that  login  shells  do  the  equivalent  of `history -L' on startup and, if
               savehist is set, `history -S' before exiting.  Because only ~/.tcshrc is  normally
               sourced  before  ~/.history,  histfile  should  be  set  in  ~/.tcshrc rather than
               ~/.login.

               If histlit is set,  the  first  and  second  forms  print  and  save  the  literal
               (unexpanded) form of the history list.

               The last form clears the history list.

       hup [command] (+)
               With  command, runs command such that it will exit on a hangup signal and arranges
               for the shell to send it a hangup signal when the shell exits.  Note that commands
               may  set  their  own  response  to  hangups, overriding hup.  Without an argument,
               causes the non-interactive shell only to exit on a hangup for the remainder of the
               script.  See also Signal handling and the nohup builtin command.

       if (expr) command
               If  expr  (an  expression,  as  described  under Expressions) evaluates true, then
               command is executed.  Variable substitution on command happens early, at the  same
               time  it  does  for the rest of the if command.  command must be a simple command,
               not an alias, a pipeline, a command list or a parenthesized command list,  but  it
               may  have  arguments.   Input/output  redirection occurs even if expr is false and
               command is thus not executed; this is a bug.

       if (expr) then
       ...
       else if (expr2) then
       ...
       else
       ...
       endif   If the specified expr is true then the commands to the first  else  are  executed;
               otherwise if expr2 is true then the commands to the second else are executed, etc.
               Any number of else-if pairs are possible; only one endif is needed.  The else part
               is  likewise  optional.  (The words else and endif must appear at the beginning of
               input lines; the if must appear alone on its input line or after an else.)

       inlib shared-library ... (+)
               Adds each shared-library to the current environment.  There is no way to remove  a
               shared library.  (Domain/OS only)

       jobs [-l]
               Lists  the  active  jobs.   With  -l,  lists process IDs in addition to the normal
               information.  On TCF systems, prints the site on which each job is executing.

       kill [-s signal] %job|pid ...
       kill -l The first and second forms sends the specified signal (or, if none is  given,  the
               TERM (terminate) signal) to the specified jobs or processes.  job may be a number,
               a string, `', `%', `+' or `-' as described under Jobs.  Signals are  either  given
               by  number  or  by name (as given in /usr/include/signal.h, stripped of the prefix
               `SIG').  There is no default job; saying just `kill' does not send a signal to the
               current  job.   If the signal being sent is TERM (terminate) or HUP (hangup), then
               the job or process is sent a CONT (continue) signal as well.  The third form lists
               the signal names.

       limit [-h] [resource [maximum-use]]
               Limits  the  consumption by the current process and each process it creates to not
               individually exceed maximum-use on the specified resource.  If no  maximum-use  is
               given,  then  the  current  limit  is  printed;  if no resource is given, then all
               limitations are given.  If the -h flag is given, the hard limits are used  instead
               of  the  current  limits.   The  hard limits impose a ceiling on the values of the
               current limits.  Only the super-user may raise the hard limits,  but  a  user  may
               lower or raise the current limits within the legal range.

               Controllable resources currently include (if supported by the OS):

               cputime
                      the maximum number of cpu-seconds to be used by each process

               filesize
                      the largest single file which can be created

               datasize
                      the  maximum  growth of the data+stack region via sbrk(2) beyond the end of
                      the program text

               stacksize
                      the maximum size of the automatically-extended stack region

               coredumpsize
                      the size of the largest core dump that will be created

               memoryuse
                      the maximum amount of physical memory a process may have allocated to it at
                      a given time

               vmemoryuse
                      the  maximum amount of virtual memory a process may have allocated to it at
                      a given time (address space)

               vmemoryuse
                      the maximum amount of virtual memory a process may have allocated to it  at
                      a given time

               heapsize
                      the maximum amount of memory a process may allocate per brk() system call

               descriptors or openfiles
                      the maximum number of open files for this process

               pseudoterminals
                      the maximum number of pseudo-terminals for this user

               kqueues
                      the maximum number of kqueues allocated for this process

               concurrency
                      the maximum number of threads for this process

               memorylocked
                      the maximum size which a process may lock into memory using mlock(2)

               maxproc
                      the maximum number of simultaneous processes for this user id

               maxthread
                      the maximum number of simultaneous threads (lightweight processes) for this
                      user id

               threads
                      the maximum number of threads for this process

               sbsize the maximum size of socket buffer usage for this user

               swapsize
                      the maximum amount of swap space reserved or used for this user

               maxlocks
                      the maximum number of locks for this user

               posixlocks
                      the maximum number of POSIX advisory locks for this user

               maxsignal
                      the maximum number of pending signals for this user

               maxmessage
                      the maximum number of bytes in POSIX mqueues for this user

               maxnice
                      the maximum nice  priority  the  user  is  allowed  to  raise  mapped  from
                      [19...-20] to [0...39] for this user

               maxrtprio
                      the  maximum  realtime  priority for this user maxrttime the timeout for RT
                      tasks in microseconds for this user.

               maximum-use may be given as a (floating point or integer)  number  followed  by  a
               scale  factor.   For  all  limits  other  than cputime the default scale is `k' or
               `kilobytes' (1024 bytes);  a  scale  factor  of  `m'  or  `megabytes'  or  `g'  or
               `gigabytes' may also be used.  For cputime the default scaling is `seconds', while
               `m' for minutes or `h' for hours, or a time of the form `mm:ss' giving minutes and
               seconds may be used.

               If  maximum-use   is `unlimited', then the limitation on the specified resource is
               removed (this is equivalent to the unlimit builtin command).

               For both resource names and scale  factors,  unambiguous  prefixes  of  the  names
               suffice.

       log (+) Prints the watch shell variable and reports on each user indicated in watch who is
               logged in, regardless of when they last logged in.  See also watchlog.

       login   Terminates a login shell, replacing it with an instance of /bin/login. This is one
               way to log off, included for compatibility with sh(1).

       logout  Terminates a login shell.  Especially useful if ignoreeof is set.

       ls-F [-switch ...] [file ...] (+)
               Lists  files  like  `ls  -F', but much faster.  It identifies each type of special
               file in the listing with a special character:

               /   Directory
               *   Executable
               #   Block device
               %   Character device
               |   Named pipe (systems with named pipes only)
               =   Socket (systems with sockets only)
               @   Symbolic link (systems with symbolic links only)
               +   Hidden directory (AIX only) or context dependent (HP/UX only)
               :   Network special (HP/UX only)

               If the listlinks shell variable is set, symbolic  links  are  identified  in  more
               detail (on only systems that have them, of course):

               @   Symbolic link to a non-directory
               >   Symbolic link to a directory
               &   Symbolic link to nowhere

               listlinks  also  slows down ls-F and causes partitions holding files pointed to by
               symbolic links to be mounted.

               If the listflags shell variable is set to `x', `a'  or  `A',  or  any  combination
               thereof (e.g., `xA'), they are used as flags to ls-F, making it act like `ls -xF',
               `ls -Fa', `ls -FA' or a combination (e.g., `ls -FxA').  On machines where `ls  -C'
               is  not the default, ls-F acts like `ls -CF', unless listflags contains an `x', in
               which case it acts like `ls -xF'.  ls-F passes its arguments to  ls(1)  if  it  is
               given any switches, so `alias ls ls-F' generally does the right thing.

               The  ls-F  builtin can list files using different colors depending on the filetype
               or extension.   See  the  color  shell  variable  and  the  LS_COLORS  environment
               variable.

       migrate [-site] pid|%jobid ... (+)
       migrate -site (+)
               The  first  form  migrates the process or job to the site specified or the default
               site determined by the system path.  The second form  is  equivalent  to  `migrate
               -site  $$':  it migrates the current process to the specified site.  Migrating the
               shell itself can cause unexpected behavior, because the shell  does  not  like  to
               lose its tty.  (TCF only)

       newgrp [-] [group] (+)
               Equivalent  to  `exec  newgrp'; see newgrp(1).  Available only if the shell was so
               compiled; see the version shell variable.

       nice [+number] [command]
               Sets the scheduling priority for the shell to number, or, without  number,  to  4.
               With  command,  runs command at the appropriate priority.  The greater the number,
               the less cpu the process gets.  The super-user may specify  negative  priority  by
               using  `nice  -number  ...'.   Command  is always executed in a sub-shell, and the
               restrictions placed on commands in simple if statements apply.

       nohup [command]
               With command, runs command such that it will ignore  hangup  signals.   Note  that
               commands  may  set  their  own  response to hangups, overriding nohup.  Without an
               argument, causes  the  non-interactive  shell  only  to  ignore  hangups  for  the
               remainder of the script.  See also Signal handling and the hup builtin command.

       notify [%job ...]
               Causes  the  shell to notify the user asynchronously when the status of any of the
               specified jobs (or, without %job, the current job)  changes,  instead  of  waiting
               until the next prompt as is usual.  job may be a number, a string, `', `%', `+' or
               `-' as described under Jobs.  See also the notify shell variable.

       onintr [-|label]
               Controls the action of the shell on interrupts.  Without arguments,  restores  the
               default  action of the shell on interrupts, which is to terminate shell scripts or
               to return to the terminal command input level.  With `-', causes all interrupts to
               be  ignored.   With  label,  causes  the  shell  to execute a `goto label' when an
               interrupt is received or a child process terminates because it was interrupted.

               onintr is ignored if the shell is running detached and  in  system  startup  files
               (see FILES), where interrupts are disabled anyway.

       popd [-p] [-l] [-n|-v] [+n]
               Without  arguments, pops the directory stack and returns to the new top directory.
               With a number `+n', discards the n'th entry in the stack.

               Finally, all forms of popd print the final directory stack, just like  dirs.   The
               pushdsilent shell variable can be set to prevent this and the -p flag can be given
               to override pushdsilent.  The -l, -n and -v flags have the same effect on popd  as
               on dirs.  (+)

       printenv [name] (+)
               Prints  the names and values of all environment variables or, with name, the value
               of the environment variable name.

       pushd [-p] [-l] [-n|-v] [name|+n]
               Without arguments, exchanges the top two elements  of  the  directory  stack.   If
               pushdtohome  is  set,  pushd  without arguments does `pushd ~', like cd.  (+) With
               name, pushes the current working directory onto the directory stack and changes to
               name.   If  name  is  `-' it is interpreted as the previous working directory (see
               Filename substitution).  (+) If dunique is set, pushd  removes  any  instances  of
               name  from  the  stack  before pushing it onto the stack.  (+) With a number `+n',
               rotates the nth element of the directory stack around to be the  top  element  and
               changes  to  it.   If  dextract  is  set,  however,  `pushd  +n'  extracts the nth
               directory, pushes it onto the top of the stack and changes to it.  (+)

               Finally, all forms of pushd print the final directory stack, just like dirs.   The
               pushdsilent shell variable can be set to prevent this and the -p flag can be given
               to override pushdsilent.  The -l, -n and -v flags have the same effect on pushd as
               on dirs.  (+)

       rehash  Causes  the  internal  hash  table  of the contents of the directories in the path
               variable to be recomputed.  This is needed if the autorehash shell variable is not
               set  and  new  commands  are added to directories in path while you are logged in.
               With autorehash, a new command will be found automatically, except in the  special
               case  where  another  command  of  the  same  name which is located in a different
               directory already exists in the hash  table.   Also  flushes  the  cache  of  home
               directories built by tilde expansion.

       repeat count command
               The specified command, which is subject to the same restrictions as the command in
               the one line if statement above, is executed count times.  I/O redirections  occur
               exactly once, even if count is 0.

       rootnode //nodename (+)
               Changes   the  rootnode  to  //nodename,  so  that  `/'  will  be  interpreted  as
               `//nodename'.  (Domain/OS only)

       sched (+)
       sched [+]hh:mm command (+)
       sched -n (+)
               The first form prints the scheduled-event list.  The sched shell variable  may  be
               set to define the format in which the scheduled-event list is printed.  The second
               form adds command to the scheduled-event list.  For example,

                   > sched 11:00 echo It\'s eleven o\'clock.

               causes the shell to echo `It's eleven o'clock.' at 11 AM.   The  time  may  be  in
               12-hour AM/PM format

                   > sched 5pm set prompt='[%h] It\'s after 5; go home: >'

               or may be relative to the current time:

                   > sched +2:15 /usr/lib/uucp/uucico -r1 -sother

               A  relative  time  specification may not use AM/PM format.  The third form removes
               item n from the event list:

                   > sched
                        1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother
                        2  Wed Apr  4 17:00  set prompt=[%h] It's after 5; go home: >
                   > sched -2
                   > sched
                        1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother

               A command in the scheduled-event list is executed just before the first prompt  is
               printed  after the time when the command is scheduled.  It is possible to miss the
               exact time when the command is to be run, but an overdue command will  execute  at
               the  next  prompt.   A command which comes due while the shell is waiting for user
               input is executed immediately.  However, normal operation  of  an  already-running
               command will not be interrupted so that a scheduled-event list element may be run.

               This  mechanism is similar to, but not the same as, the at(1) command on some Unix
               systems.  Its major disadvantage is that it may not run a command at  exactly  the
               specified  time.  Its major advantage is that because sched runs directly from the
               shell, it has access to shell variables and other  structures.   This  provides  a
               mechanism for changing one's working environment based on the time of day.

       set
       set name ...
       set name=word ...
       set [-r] [-f|-l] name=(wordlist) ... (+)
       set name[index]=word ...
       set -r (+)
       set -r name ... (+)
       set -r name=word ... (+)
               The  first form of the command prints the value of all shell variables.  Variables
               which contain more than a single word print as a  parenthesized  word  list.   The
               second  form sets name to the null string.  The third form sets name to the single
               word.  The fourth form sets name to the list of words in wordlist.  In  all  cases
               the  value is command and filename expanded.  If -r is specified, the value is set
               read-only.  If -f or -l are specified, set only unique words keeping their  order.
               -f  prefers  the first occurrence of a word, and -l the last.  The fifth form sets
               the index'th component of name to word; this component must  already  exist.   The
               sixth  form  lists  only the names of all shell variables that are read-only.  The
               seventh form makes name read-only, whether or not it has a value.  The eighth form
               is the same as the third form, but make name read-only at the same time.

               These arguments can be repeated to set and/or make read-only multiple variables in
               a single set command.  Note, however, that  variable  expansion  happens  for  all
               arguments  before  any setting occurs.  Note also that `=' can be adjacent to both
               name and word or separated from both by whitespace, but cannot be adjacent to only
               one or the other.  See also the unset builtin command.

       setenv [name [value]]
               Without  arguments,  prints  the  names  and  values of all environment variables.
               Given name, sets the environment variable name to value or, without value, to  the
               null string.

       setpath path (+)
               Equivalent to setpath(1).  (Mach only)

       setspath LOCAL|site|cpu ... (+)
               Sets the system execution path.  (TCF only)

       settc cap value (+)
               Tells  the  shell  to  believe  that  the  terminal  capability cap (as defined in
               termcap(5)) has the value value.  No sanity checking is  done.   Concept  terminal
               users may have to `settc xn no' to get proper wrapping at the rightmost column.

       setty [-d|-q|-x] [-a] [[+|-]mode] (+)
               Controls  which  tty  modes  (see Terminal management) the shell does not allow to
               change.  -d, -q or -x tells setty to act on the `edit', `quote' or  `execute'  set
               of tty modes respectively; without -d, -q or -x, `execute' is used.

               Without  other  arguments, setty lists the modes in the chosen set which are fixed
               on (`+mode') or off (`-mode').  The available modes, and thus  the  display,  vary
               from  system to system.  With -a, lists all tty modes in the chosen set whether or
               not they are fixed.  With +mode, -mode or mode, fixes mode on or  off  or  removes
               control  from  mode  in  the  chosen set.  For example, `setty +echok echoe' fixes
               `echok' mode on and allows commands to turn `echoe' mode on or off, both when  the
               shell is executing commands.

       setxvers [string] (+)
               Set the experimental version prefix to string, or removes it if string is omitted.
               (TCF only)

       shift [variable]
               Without arguments, discards argv[1] and shifts the members of argv  to  the  left.
               It  is  an  error  for  argv not to be set or to have less than one word as value.
               With variable, performs the same function on variable.

       source [-h] name [args ...]
               The shell reads and executes commands from name.  The commands are not  placed  on
               the  history  list.   If  any args are given, they are placed in argv.  (+) source
               commands may be nested; if they are nested too deeply the shell  may  run  out  of
               file  descriptors.  An error in a source at any level terminates all nested source
               commands.  With -h, commands are placed on  the  history  list  instead  of  being
               executed, much like `history -L'.

       stop %job|pid ...
               Stops  the specified jobs or processes which are executing in the background.  job
               may be a number, a string, `', `%', `+' or `-' as described under Jobs.  There  is
               no default job; saying just `stop' does not stop the current job.

       suspend Causes  the shell to stop in its tracks, much as if it had been sent a stop signal
               with ^Z.  This is most often used to stop shells started by su(1).

       switch (string)
       case str1:
           ...
           breaksw
       ...
       default:
           ...
           breaksw
       endsw   Each case label is successively matched, against the  specified  string  which  is
               first command and filename expanded.  The file metacharacters `*', `?' and `[...]'
               may be used in the case labels, which are  variable  expanded.   If  none  of  the
               labels  match  before  a `default' label is found, then the execution begins after
               the default label.  Each case label and the  default  label  must  appear  at  the
               beginning  of  a line.  The command breaksw causes execution to continue after the
               endsw.  Otherwise control may fall through case labels and default labels as in C.
               If no label matches and there is no default, execution continues after the endsw.

       telltc (+)
               Lists the values of all terminal capabilities (see termcap(5)).

       termname [terminal type] (+)
               Tests if terminal type (or the current value of TERM if no terminal type is given)
               has an entry in the hosts termcap(5) or terminfo(5) database. Prints the  terminal
               type to stdout and returns 0 if an entry is present otherwise returns 1.

       time [command]
               Executes  command  (which  must  be  a simple command, not an alias, a pipeline, a
               command list or a parenthesized  command  list)  and  prints  a  time  summary  as
               described  under  the  time  variable.  If necessary, an extra shell is created to
               print the time statistic when the command completes.  Without  command,  prints  a
               time summary for the current shell and its children.

       umask [value]
               Sets  the file creation mask to value, which is given in octal.  Common values for
               the mask are 002, giving all access to the group and read and  execute  access  to
               others,  and 022, giving read and execute access to the group and others.  Without
               value, prints the current file creation mask.

       unalias pattern
               Removes all aliases whose names match  pattern.   `unalias  *'  thus  removes  all
               aliases.  It is not an error for nothing to be unaliased.

       uncomplete pattern (+)
               Removes  all  completions  whose names match pattern.  `uncomplete *' thus removes
               all completions.  It is not an error for nothing to be uncompleted.

       unhash  Disables use of the internal hash table to speed location of executed programs.

       universe universe (+)
               Sets the universe to universe.  (Masscomp/RTU only)

       unlimit [-hf] [resource]
               Removes the limitation on resource or, if no resource is specified,  all  resource
               limitations.  With -h, the corresponding hard limits are removed.  Only the super-
               user may do this.  Note that unlimit may not exit successful, since  most  systems
               do not allow descriptors to be unlimited.  With -f errors are ignored.

       unset pattern
               Removes  all  variables  whose  names  match  pattern,  unless they are read-only.
               `unset *' thus removes all variables unless they are  read-only;  this  is  a  bad
               idea.  It is not an error for nothing to be unset.

       unsetenv pattern
               Removes  all  environment  variables whose names match pattern.  `unsetenv *' thus
               removes all environment variables; this is a bad idea.  It is  not  an  error  for
               nothing to be unsetenved.

       ver [systype [command]] (+)
               Without  arguments,  prints SYSTYPE.  With systype, sets SYSTYPE to systype.  With
               systype and command, executes command under systype.  systype may be  `bsd4.3'  or
               `sys5.3'.  (Domain/OS only)

       wait    The  shell  waits  for  all  background  jobs.   If  the  shell is interactive, an
               interrupt will disrupt the wait and cause the shell to print  the  names  and  job
               numbers of all outstanding jobs.

       warp universe (+)
               Sets the universe to universe.  (Convex/OS only)

       watchlog (+)
               An alternate name for the log builtin command (q.v.).  Available only if the shell
               was so compiled; see the version shell variable.

       where command (+)
               Reports  all  known  instances  of  command,  including  aliases,   builtins   and
               executables in path.

       which command (+)
               Displays  the command that will be executed by the shell after substitutions, path
               searching, etc.  The builtin command is  just  like  which(1),  but  it  correctly
               reports  tcsh  aliases  and  builtins and is 10 to 100 times faster.  See also the
               which-command editor command.

       while (expr)
       ...
       end     Executes the commands between the while  and  the  matching  end  while  expr  (an
               expression,  as  described  under  Expressions) evaluates non-zero.  while and end
               must appear alone on their input  lines.   break  and  continue  may  be  used  to
               terminate  or continue the loop prematurely.  If the input is a terminal, the user
               is prompted the first time through the loop as with foreach.

   Special aliases (+)
       If set, each of these aliases executes automatically at the indicated time.  They are  all
       initially undefined.

       beepcmd Runs when the shell wants to ring the terminal bell.

       cwdcmd  Runs after every change of working directory.  For example, if the user is working
               on an X window system using  xterm(1)  and  a  re-parenting  window  manager  that
               supports title bars such as twm(1) and does

                   > alias cwdcmd  'echo -n "^[]2;${HOST}:$cwd ^G"'

               then the shell will change the title of the running xterm(1) to be the name of the
               host, a colon, and the full current working directory.  A fancier way to  do  that
               is

                   > alias cwdcmd 'echo -n "^[]2;${HOST}:$cwd^G^[]1;${HOST}^G"'

               This  will  put  the  hostname and working directory on the title bar but only the
               hostname in the icon manager menu.

               Note that putting a cd, pushd or popd in cwdcmd may cause an infinite loop.  It is
               the author's opinion that anyone doing so will get what they deserve.

       jobcmd  Runs  before  each command gets executed, or when the command changes state.  This
               is similar to postcmd, but it does not print builtins.

                   > alias jobcmd  'echo -n "^[]2\;\!#:q^G"'

               then executing vi foo.c will put the command string in the xterm title bar.

       helpcommand
               Invoked by the run-help editor command.  The command name for which help is sought
               is passed as sole argument.  For example, if one does

                   > alias helpcommand '\!:1 --help'

               then  the  help  display of the command itself will be invoked, using the GNU help
               calling convention.  Currently there is no easy way to account for various calling
               conventions  (e.g.,  the  customary  Unix  `-h'),  except by using a table of many
               commands.

       periodic
               Runs every tperiod minutes.  This provides a  convenient  means  for  checking  on
               common but infrequent changes such as new mail.  For example, if one does

                   > set tperiod = 30
                   > alias periodic checknews

               then  the  checknews(1)  program  runs  every  30 minutes.  If periodic is set but
               tperiod is unset or set to 0, periodic behaves like precmd.

       precmd  Runs just before each prompt is printed.  For example, if one does

                   > alias precmd date

               then date(1) runs just before the shell prompts for each command.   There  are  no
               limits on what precmd can be set to do, but discretion should be used.

       postcmd Runs before each command gets executed.

                   > alias postcmd  'echo -n "^[]2\;\!#:q^G"'

               then executing vi foo.c will put the command string in the xterm title bar.

       shell   Specifies  the  interpreter for executable scripts which do not themselves specify
               an interpreter.  The first word  should  be  a  full  path  name  to  the  desired
               interpreter (e.g., `/bin/csh' or `/usr/local/bin/tcsh').

   Special shell variables
       The variables described in this section have special meaning to the shell.

       The  shell  sets  addsuffix, argv, autologout, csubstnonl, command, echo_style, edit, gid,
       group, home, loginsh, oid, path, prompt, prompt2, prompt3, shell, shlvl, tcsh, term,  tty,
       uid,  user  and  version  at  startup; they do not change thereafter unless changed by the
       user.  The shell updates cwd, dirstack, owd and status when necessary, and sets logout  on
       logout.

       The  shell  synchronizes  group,  home,  path,  shlvl,  term and user with the environment
       variables of the same names: whenever the environment variable changes the  shell  changes
       the  corresponding  shell  variable  to match (unless the shell variable is read-only) and
       vice versa.  Note that although  cwd  and  PWD  have  identical  meanings,  they  are  not
       synchronized  in  this  manner,  and  that  the  shell  automatically converts between the
       different formats of path and PATH.

       addsuffix (+)
               If set, filename completion adds `/' to the end of directories and a space to  the
               end of normal files when they are matched exactly.  Set by default.

       afsuser (+)
               If set, autologout's autolock feature uses its value instead of the local username
               for kerberos authentication.

       ampm (+)
               If set, all times are shown in 12-hour AM/PM format.

       anyerror (+)
               This variable selects what is propagated to the value of the status variable.  For
               more information see the description of the status variable below.

       argv    The arguments to the shell.  Positional parameters are taken from argv, i.e., `$1'
               is replaced by `$argv[1]', etc.  Set by default, but usually empty in  interactive
               shells.

       autocorrect (+)
               If  set,  the  spell-word  editor  command  is  invoked  automatically before each
               completion attempt.

       autoexpand (+)
               If set, the expand-history editor command is  invoked  automatically  before  each
               completion  attempt.  If  this  is  set  to onlyhistory, then only history will be
               expanded and a second completion will expand filenames.

       autolist (+)
               If set, possibilities are  listed  after  an  ambiguous  completion.   If  set  to
               `ambiguous',  possibilities  are  listed  only when no new characters are added by
               completion.

       autologout (+)
               The first word is the number of minutes of  inactivity  before  automatic  logout.
               The  optional  second word is the number of minutes of inactivity before automatic
               locking.  When the shell automatically logs out, it prints `auto-logout', sets the
               variable logout to `automatic' and exits.  When the shell automatically locks, the
               user is required to enter  his  password  to  continue  working.   Five  incorrect
               attempts  result  in  automatic  logout.   Set  to `60' (automatic logout after 60
               minutes, and no locking) by default in login and superuser shells, but not if  the
               shell  thinks  it  is running under a window system (i.e., the DISPLAY environment
               variable is set), the tty is a pseudo-tty (pty) or the shell was not  so  compiled
               (see  the  version  shell  variable).   See  also  the  afsuser  and  logout shell
               variables.

       autorehash (+)
               If set, the internal hash table of the contents of the  directories  in  the  path
               variable  will  be  recomputed  if  a  command is not found in the hash table.  In
               addition, the list  of  available  commands  will  be  rebuilt  for  each  command
               completion  or  spelling  correction  attempt  if  set  to `complete' or `correct'
               respectively; if set to `always', this will be done for both cases.

       backslash_quote (+)
               If set, backslashes (`\') always quote `\', `'', and `"'.  This may  make  complex
               quoting tasks easier, but it can cause syntax errors in csh(1) scripts.

       catalog The  file  name  of  the message catalog.  If set, tcsh use `tcsh.${catalog}' as a
               message catalog instead of default `tcsh'.

       cdpath  A list of directories in which cd should search for subdirectories if they  aren't
               found in the current directory.

       cdtohome (+)
               If not set, cd requires a directory name, and will not go to the home directory if
               it's omitted.  This is set by default.

       color   If set, it enables color display for the builtin ls-F and it  passes  --color=auto
               to  ls.   Alternatively,  it can be set to only ls-F or only ls to enable color to
               only one command.  Setting it to nothing is equivalent to setting it to (ls-F ls).

       colorcat
               If set, it enables color escape sequence  for  NLS  message  files.   And  display
               colorful NLS messages.

       command (+)
               If set, the command which was passed to the shell with the -c flag (q.v.).

       compat_expr (+)
               If set, the shell will evaluate expressions right to left, like the original csh.

       complete (+)
               If  set  to  `igncase',  the  completion  becomes  case  insensitive.   If  set to
               `enhance', completion ignores case and considers hyphens  and  underscores  to  be
               equivalent; it will also treat periods, hyphens and underscores (`.', `-' and `_')
               as word separators.   If  set  to  `Enhance',  completion  matches  uppercase  and
               underscore  characters  explicitly  and  matches  lowercase and hyphens in a case-
               insensitive manner; it  will  treat  periods,  hyphens  and  underscores  as  word
               separators.

       continue (+)
               If set to a list of commands, the shell will continue the listed commands, instead
               of starting a new one.

       continue_args (+)
               Same as continue, but the shell will execute:

                   echo `pwd` $argv > ~/.<cmd>_pause; %<cmd>

       correct (+)
               If set to  `cmd',  commands  are  automatically  spelling-corrected.   If  set  to
               `complete',  commands  are  automatically  completed.  If set to `all', the entire
               command line is corrected.

       csubstnonl (+)
               If set, newlines and carriage returns in  command  substitution  are  replaced  by
               spaces.  Set by default.

       cwd     The  full  pathname of the current directory.  See also the dirstack and owd shell
               variables.

       dextract (+)
               If set, `pushd +n' extracts the nth directory from the directory stack rather than
               rotating it to the top.

       dirsfile (+)
               The default location in which `dirs -S' and `dirs -L' look for a history file.  If
               unset, ~/.cshdirs is used.  Because only  ~/.tcshrc  is  normally  sourced  before
               ~/.cshdirs, dirsfile should be set in ~/.tcshrc rather than ~/.login.

       dirstack (+)
               An  array  of  all  the directories on the directory stack.  `$dirstack[1]' is the
               current working directory, `$dirstack[2]' the first directory on the  stack,  etc.
               Note  that  the  current working directory is `$dirstack[1]' but `=0' in directory
               stack substitutions, etc.   One  can  change  the  stack  arbitrarily  by  setting
               dirstack, but the first element (the current working directory) is always correct.
               See also the cwd and owd shell variables.

       dspmbyte (+)
               Has an effect iff 'dspm' is listed as part of the version shell variable.  If  set
               to  `euc',  it  enables  display  and editing EUC-kanji(Japanese) code.  If set to
               `sjis', it enables display  and  editing  Shift-JIS(Japanese)  code.   If  set  to
               `big5',  it  enables display and editing Big5(Chinese) code.  If set to `utf8', it
               enables display and editing Utf8(Unicode) code.  If set to the  following  format,
               it enables display and editing of original multi-byte code format:

                   > set dspmbyte = 0000....(256 bytes)....0000

               The  table  requires just 256 bytes.  Each character of 256 characters corresponds
               (from left to right) to the ASCII codes 0x00, 0x01, ... 0xff.  Each  character  is
               set to number 0,1,2 and 3.  Each number has the following meaning:
                 0 ... not used for multi-byte characters.
                 1 ... used for the first byte of a multi-byte character.
                 2 ... used for the second byte of a multi-byte character.
                 3 ... used for both the first byte and second byte of a multi-byte character.

                 Example:
               If  set to `001322', the first character (means 0x00 of the ASCII code) and second
               character (means 0x01 of ASCII code) are set to `0'.  Then, it  is  not  used  for
               multi-byte characters.  The 3rd character (0x02) is set to '1', indicating that it
               is used for the first byte of a multi-byte character.  The 4th character(0x03)  is
               set  '3'.   It is used for both the first byte and the second byte of a multi-byte
               character.  The 5th and 6th characters (0x04,0x05) are set to '2', indicating that
               they are used for the second byte of a multi-byte character.

               The GNU fileutils version of ls cannot display multi-byte filenames without the -N
               ( --literal ) option.   If you are using this version,  set  the  second  word  of
               dspmbyte  to  "ls".   If  not,  for  example,  "ls-F -l" cannot display multi-byte
               filenames.

                 Note:
               This variable can only be used if KANJI and DSPMBYTE has been defined  at  compile
               time.

       dunique (+)
               If  set, pushd removes any instances of name from the stack before pushing it onto
               the stack.

       echo    If set, each command with its arguments is echoed just before it is executed.  For
               non-builtin  commands  all  expansions occur before echoing.  Builtin commands are
               echoed before command and filename substitution, because these  substitutions  are
               then done selectively.  Set by the -x command line option.

       echo_style (+)
               The style of the echo builtin.  May be set to

               bsd     Don't echo a newline if the first argument is `-n'; the default for csh.
               sysv    Recognize backslashed escape sequences in echo strings.
               both    Recognize both the `-n' flag and backslashed escape sequences; the default
                       for tcsh.
               none    Recognize neither.

               Set by default to the local system default.  The BSD  and  System  V  options  are
               described in the echo(1) man pages on the appropriate systems.

       edit (+)
               If set, the command-line editor is used.  Set by default in interactive shells.

       editors (+)
               A  list  of  command  names for the run-fg-editor editor command to match.  If not
               set, the EDITOR (`ed' if unset) and VISUAL (`vi' if unset)  environment  variables
               will be used instead.

       ellipsis (+)
               If  set,  the  `%c'/`%.' and `%C' prompt sequences (see the prompt shell variable)
               indicate skipped directories with an ellipsis (`...')  instead of `/<skipped>'.

       euid (+)
               The user's effective user ID.

       euser (+)
               The first matching passwd entry name corresponding to the effective user ID.

       fignore (+)
               Lists file name suffixes to be ignored by completion.

       filec   In tcsh, completion is always used and this variable is  ignored  by  default.  If
               edit  is  unset,  then  the  traditional  csh  completion is used.  If set in csh,
               filename completion is used.

       gid (+) The user's real group ID.

       globdot (+)
               If set, wild-card glob patterns will match files and  directories  beginning  with
               `.' except for `.' and `..'

       globstar (+)
               If  set, the `**' and `***' file glob patterns will match any string of characters
               including `/' traversing any existing sub-directories.  (e.g.  `ls **.c' will list
               all the .c files in the current directory tree).  If used by itself, it will match
               zero or more sub-directories (e.g. `ls /usr/include/**/time.h' will list any  file
               named    `time.h'    in    the    /usr/include   directory   tree;   whereas   `ls
               /usr/include/**time.h' will match any file  in  the  /usr/include  directory  tree
               ending  in  `time.h').   To prevent problems with recursion, the `**' glob-pattern
               will not descend into a symbolic link containing a directory.  To  override  this,
               use `***'

       group (+)
               The user's group name.

       highlight
               If  set,  the incremental search match (in i-search-back and i-search-fwd) and the
               region between the mark and the cursor are highlighted in reverse video.

               Highlighting requires  more  frequent  terminal  writes,  which  introduces  extra
               overhead.  If  you  care  about  terminal  performance, you may want to leave this
               unset.

       histchars
               A string value determining the characters used  in  History  substitution  (q.v.).
               The  first  character  of its value is used as the history substitution character,
               replacing the default character `!'.  The second character of its  value  replaces
               the character `^' in quick substitutions.

       histdup (+)
               Controls  handling of duplicate entries in the history list.  If set to `all' only
               unique history events are entered in the history list.  If set to `prev'  and  the
               last history event is the same as the current command, then the current command is
               not entered in the history.  If set to `erase' and the same event is found in  the
               history  list, that old event gets erased and the current one gets inserted.  Note
               that the `prev' and `all' options renumber history events so there are no gaps.

       histfile (+)
               The default location in which `history -S' and `history -L'  look  for  a  history
               file.   If  unset,  ~/.history  is used.  histfile is useful when sharing the same
               home directory between different machines, or when saving  separate  histories  on
               different   terminals.    Because   only  ~/.tcshrc  is  normally  sourced  before
               ~/.history, histfile should be set in ~/.tcshrc rather than ~/.login.

       histlit (+)
               If set, builtin and editor commands and the savehist  mechanism  use  the  literal
               (unexpanded)  form  of  lines  in  the history list.  See also the toggle-literal-
               history editor command.

       history The first word indicates the number of  history  events  to  save.   The  optional
               second  word  (+)  indicates the format in which history is printed; if not given,
               `%h\t%T\t%R\n' is used.  The format sequences are described  below  under  prompt;
               note the variable meaning of `%R'.  Set to `100' by default.

       home    Initialized  to  the home directory of the invoker.  The filename expansion of `~'
               refers to this variable.

       ignoreeof
               If set to the empty string or `0' and the input device is a terminal, the  end-of-
               file  command  (usually  generated  by  the  user by typing `^D' on an empty line)
               causes the shell to print `Use "exit" to leave tcsh.' instead  of  exiting.   This
               prevents  the  shell  from  accidentally  being killed.  Historically this setting
               exited after 26 successive EOF's to avoid infinite loops.  If set to a  number  n,
               the  shell  ignores  n  - 1 consecutive end-of-files and exits on the nth.  (+) If
               unset, `1' is used, i.e., the shell exits on a single `^D'.

       implicitcd (+)
               If set, the shell treats a directory name typed as a command as though it  were  a
               request  to  change to that directory.  If set to verbose, the change of directory
               is echoed to the standard output.  This behavior is inhibited  in  non-interactive
               shell scripts, or for command strings with more than one word.  Changing directory
               takes precedence over executing a like-named command, but it is done  after  alias
               substitutions.  Tilde and variable expansions work as expected.

       inputmode (+)
               If  set  to  `insert'  or `overwrite', puts the editor into that input mode at the
               beginning of each line.

       killdup (+)
               Controls handling of duplicate entries in the kill ring.  If  set  to  `all'  only
               unique strings are entered in the kill ring.  If set to `prev' and the last killed
               string is the same as the current killed string, then the current  string  is  not
               entered  in  the ring.  If set to `erase' and the same string is found in the kill
               ring, the old string is erased and the current one is inserted.

       killring (+)
               Indicates the number of killed strings to keep in memory.  Set to `30' by default.
               If  unset  or  set  to  less  than `2', the shell will only keep the most recently
               killed string.  Strings are put in the killring by the editor commands that delete
               (kill)  strings of text, e.g. backward-delete-word, kill-line, etc, as well as the
               copy-region-as-kill command.  The yank editor command will yank the most  recently
               killed  string  into the command-line, while yank-pop (see Editor commands) can be
               used to yank earlier killed strings.

       listflags (+)
               If set to `x', `a' or `A', or any combination thereof (e.g., `xA'), they are  used
               as flags to ls-F, making it act like `ls -xF', `ls -Fa', `ls -FA' or a combination
               (e.g., `ls -FxA'): `a' shows all files (even if they start with a `.'), `A'  shows
               all  files  but `.' and `..', and `x' sorts across instead of down.  If the second
               word of listflags is set, it is used as the path to `ls(1)'.

       listjobs (+)
               If set, all jobs are listed when a job  is  suspended.   If  set  to  `long',  the
               listing is in long format.

       listlinks (+)
               If  set,  the  ls-F  builtin command shows the type of file to which each symbolic
               link points.

       listmax (+)
               The maximum number of items  which  the  list-choices  editor  command  will  list
               without asking first.

       listmaxrows (+)
               The  maximum  number  of  rows of items which the list-choices editor command will
               list without asking first.

       loginsh (+)
               Set by the shell if it is a login shell.  Setting or unsetting it within  a  shell
               has no effect.  See also shlvl.

       logout (+)
               Set  by  the  shell  to  `normal'  before  a  normal logout, `automatic' before an
               automatic logout, and `hangup' if the shell was killed by  a  hangup  signal  (see
               Signal handling).  See also the autologout shell variable.

       mail    A list of files and directories to check for incoming mail, optionally preceded by
               a numeric word.  Before each prompt, if 10 minutes  have  passed  since  the  last
               check,  the  shell  checks  each  file  and says `You have new mail.' (or, if mail
               contains multiple files, `You have new mail in name.') if the filesize is  greater
               than zero in size and has a modification time greater than its access time.

               If  you  are  in  a  login shell, then no mail file is reported unless it has been
               modified  after  the  time  the  shell  has  started  up,  to  prevent   redundant
               notifications.   Most  login  programs  will tell you whether or not you have mail
               when you log in.

               If a file specified in mail is a directory, the shell will count each file  within
               that  directory as a separate message, and will report `You have n mails.' or `You
               have n mails in name.' as appropriate.  This functionality is  provided  primarily
               for those systems which store mail in this manner, such as the Andrew Mail System.

               If  the  first  word  of  mail is numeric it is taken as a different mail checking
               interval, in seconds.

               Under very rare circumstances, the shell may report `You have  mail.'  instead  of
               `You have new mail.'

       matchbeep (+)
               If  set  to  `never',  completion never beeps.  If set to `nomatch', it beeps only
               when there is no match.  If set to `ambiguous', it beeps when there  are  multiple
               matches.  If set to `notunique', it beeps when there is one exact and other longer
               matches.  If unset, `ambiguous' is used.

       nobeep (+)
               If set, beeping is completely disabled.  See also visiblebell.

       noclobber
               If set, restrictions are placed on output redirection to insure that files are not
               accidentally  destroyed  and  that  `>>'  redirections refer to existing files, as
               described in the Input/output section.

       noding  If set, disable the printing of `DING!' in  the  prompt  time  specifiers  at  the
               change of hour.

       noglob  If  set,  Filename  substitution  and  Directory  stack  substitution  (q.v.)  are
               inhibited.  This is most useful in shell scripts which do not deal with filenames,
               or  after  a  list  of  filenames has been obtained and further expansions are not
               desirable.

       nokanji (+)
               If set and the shell supports Kanji  (see  the  version  shell  variable),  it  is
               disabled so that the meta key can be used.

       nonomatch
               If  set, a Filename substitution or Directory stack substitution (q.v.) which does
               not match any existing files is left untouched rather than causing an  error.   It
               is still an error for the substitution to be malformed, e.g., `echo [' still gives
               an error.

       nostat (+)
               A list of directories (or glob-patterns  which  match  directories;  see  Filename
               substitution) that should not be stat(2)ed during a completion operation.  This is
               usually used to exclude directories which take  too  much  time  to  stat(2),  for
               example /afs.

       notify  If  set,  the  shell  announces job completions asynchronously.  The default is to
               present job completions just before printing a prompt.

       oid (+) The user's real organization ID.  (Domain/OS only)

       owd (+) The old working directory, equivalent to the `-' used by cd and pushd.   See  also
               the cwd and dirstack shell variables.

       padhour If  set,  enable the printing of padding '0' for hours, in 24 and 12 hour formats.
               E.G.: 07:45:42 vs. 7:45:42.

       parseoctal
               To retain compatibily with older versions numeric variables starting  with  0  are
               not interpreted as octal. Setting this variable enables proper octal parsing.

       path    A  list  of  directories  in  which  to look for executable commands.  A null word
               specifies the current directory.  If there is no path variable then only full path
               names will execute.  path is set by the shell at startup from the PATH environment
               variable or, if PATH does not exist, to a system-dependent default something  like
               `(/usr/local/bin  /usr/bsd /bin /usr/bin .)'.  The shell may put `.' first or last
               in path or omit it entirely depending on how it  was  compiled;  see  the  version
               shell  variable.   A  shell which is given neither the -c nor the -t option hashes
               the contents of the directories in path after reading ~/.tcshrc and each time path
               is  reset.   If  one  adds a new command to a directory in path while the shell is
               active, one may need to do a rehash for the shell to find it.

       printexitvalue (+)
               If set and an interactive program exits with a non-zero status, the  shell  prints
               `Exit status'.

       prompt  The string which is printed before reading each command from the terminal.  prompt
               may include any of the following formatting sequences (+), which are  replaced  by
               the given information:

               %/  The current working directory.
               %~  The  current  working  directory, but with one's home directory represented by
                   `~' and other users' home directories represented by `~user' as  per  Filename
                   substitution.  `~user' substitution happens only if the shell has already used
                   `~user' in a pathname in the current session.
               %c[[0]n], %.[[0]n]
                   The trailing component  of  the  current  working  directory,  or  n  trailing
                   components if a digit n is given.  If n begins with `0', the number of skipped
                   components   precede    the    trailing    component(s)    in    the    format
                   `/<skipped>trailing'.    If  the  ellipsis  shell  variable  is  set,  skipped
                   components are represented by an ellipsis so the whole becomes  `...trailing'.
                   `~'  substitution  is  done as in `%~' above, but the `~' component is ignored
                   when counting trailing components.
               %C  Like %c, but without `~' substitution.
               %h, %!, !
                   The current history event number.
               %M  The full hostname.
               %m  The hostname up to the first `.'.
               %S (%s)
                   Start (stop) standout mode.
               %B (%b)
                   Start (stop) boldfacing mode.
               %U (%u)
                   Start (stop) underline mode.
               %t, %@
                   The time of day in 12-hour AM/PM format.
               %T  Like `%t', but in 24-hour format (but see the ampm shell variable).
               %p  The `precise' time of day in 12-hour AM/PM format, with seconds.
               %P  Like `%p', but in 24-hour format (but see the ampm shell variable).
               \c  c is parsed as in bindkey.
               ^c  c is parsed as in bindkey.
               %%  A single `%'.
               %n  The user name.
               %N  The effective user name.
               %j  The number of jobs.
               %d  The weekday in `Day' format.
               %D  The day in `dd' format.
               %w  The month in `Mon' format.
               %W  The month in `mm' format.
               %y  The year in `yy' format.
               %Y  The year in `yyyy' format.
               %l  The shell's tty.
               %L  Clears from the end of the prompt to end of the display  or  the  end  of  the
                   line.
               %$  Expands the shell or environment variable name immediately after the `$'.
               %#  `>'  (or  the  first  character  of the promptchars shell variable) for normal
                   users, `#' (or the second character of promptchars) for the superuser.
               %{string%}
                   Includes string as a literal escape sequence.   It  should  be  used  only  to
                   change  terminal  attributes  and  should  not move the cursor location.  This
                   cannot be the last sequence in prompt.
               %?  The return code of the command executed just before the prompt.
               %R  In prompt2, the status of the parser.  In prompt3, the corrected  string.   In
                   history, the history string.

               `%B',  `%S',  `%U'  and `%{string%}' are available in only eight-bit-clean shells;
               see the version shell variable.

               The bold, standout and  underline  sequences  are  often  used  to  distinguish  a
               superuser shell.  For example,

                   > set prompt = "%m [%h] %B[%@]%b [%/] you rang? "
                   tut [37] [2:54pm] [/usr/accts/sys] you rang? _

               If  `%t',  `%@',  `%T',  `%p',  or `%P' is used, and noding is not set, then print
               `DING!' on the change of hour (i.e, `:00' minutes) instead of the actual time.

               Set by default to `%# ' in interactive shells.

       prompt2 (+)
               The string with which to prompt in while and foreach loops and after lines  ending
               in  `\'.   The  same  format  sequences  may be used as in prompt (q.v.); note the
               variable meaning of `%R'.  Set by default to `%R? ' in interactive shells.

       prompt3 (+)
               The string with which to prompt when  confirming  automatic  spelling  correction.
               The  same  format  sequences  may  be  used as in prompt (q.v.); note the variable
               meaning of `%R'.  Set by  default  to  `CORRECT>%R  (y|n|e|a)?  '  in  interactive
               shells.

       promptchars (+)
               If  set  (to  a  two-character string), the `%#' formatting sequence in the prompt
               shell variable is replaced with the first  character  for  normal  users  and  the
               second character for the superuser.

       pushdtohome (+)
               If set, pushd without arguments does `pushd ~', like cd.

       pushdsilent (+)
               If set, pushd and popd do not print the directory stack.

       recexact (+)
               If set, completion completes on an exact match even if a longer match is possible.

       recognize_only_executables (+)
               If  set,  command  listing  displays  only  files in the path that are executable.
               Slow.

       rmstar (+)
               If set, the user is prompted before `rm *' is executed.

       rprompt (+)
               The string to print on the right-hand side of the screen (after the command input)
               when the prompt is being displayed on the left.  It recognizes the same formatting
               characters as prompt.  It will automatically disappear and reappear as  necessary,
               to  ensure  that command input isn't obscured, and will appear only if the prompt,
               command input, and itself will fit together on the first line.  If edit isn't set,
               then rprompt will be printed after the prompt and before the command input.

       savedirs (+)
               If  set,  the  shell does `dirs -S' before exiting.  If the first word is set to a
               number, at most that many directory stack entries are saved.

       savehist
               If set, the shell does `history -S' before exiting.  If the first word is set to a
               number,  at  most  that  many lines are saved.  (The number should be less than or
               equal to the number history entries; if it is set to greater than  the  number  of
               history settings, only history entries will be saved) If the second word is set to
               `merge', the history list is merged with the  existing  history  file  instead  of
               replacing it (if there is one) and sorted by time stamp and the most recent events
               are retained.  If the second word of savehist is `merge' and the third word is set
               to  `lock',  the  history file update will be serialized with other shell sessions
               that would possibly like to merge history at exactly the same time. (+)

       sched (+)
               The format in which the sched builtin command  prints  scheduled  events;  if  not
               given,  `%h\t%T\t%R\n'  is  used.   The format sequences are described above under
               prompt; note the variable meaning of `%R'.

       shell   The file in which the shell resides.  This is used in forking shells to  interpret
               files  which  have  execute  bits set, but which are not executable by the system.
               (See the description of Builtin and non-builtin command  execution.)   Initialized
               to the (system-dependent) home of the shell.

       shlvl (+)
               The number of nested shells.  Reset to 1 in login shells.  See also loginsh.

       status  The  exit status from the last command or backquote expansion, or any command in a
               pipeline is propagated to status.  (This is also the default csh behavior.)   This
               default  does  not  match  what  POSIX  mandates (to return the status of the last
               command only). To match the POSIX behavior, you need to unset anyerror.

               If the anyerror variable is unset, the exit status of  a  pipeline  is  determined
               only  from  the  last  command in the pipeline, and the exit status of a backquote
               expansion is not propagated to status.

               If a command terminated abnormally, then 0200 is added  to  the  status.   Builtin
               commands  which  fail  return  exit  status `1', all other builtin commands return
               status `0'.

       symlinks (+)
               Can be set to several  different  values  to  control  symbolic  link  (`symlink')
               resolution:

               If  set  to  `chase',  whenever  the  current  directory  changes  to  a directory
               containing a symbolic link, it is expanded to the real name of  the  directory  to
               which  the link points.  This does not work for the user's home directory; this is
               a bug.

               If set to `ignore', the shell tries to construct a current directory  relative  to
               the  current directory before the link was crossed.  This means that cding through
               a symbolic link and then `cd ..'ing returns one to the original  directory.   This
               affects only builtin commands and filename completion.

               If  set  to  `expand', the shell tries to fix symbolic links by actually expanding
               arguments which look  like  path  names.   This  affects  any  command,  not  just
               builtins.  Unfortunately, this does not work for hard-to-recognize filenames, such
               as those embedded in command options.  Expansion  may  be  prevented  by  quoting.
               While  this setting is usually the most convenient, it is sometimes misleading and
               sometimes confusing when it  fails  to  recognize  an  argument  which  should  be
               expanded.   A  compromise is to use `ignore' and use the editor command normalize-
               path (bound by default to ^X-n) when necessary.

               Some examples are in order.  First, let's set up some play directories:

                   > cd /tmp
                   > mkdir from from/src to
                   > ln -s from/src to/dst

               Here's the behavior with symlinks unset,

                   > cd /tmp/to/dst; echo $cwd
                   /tmp/to/dst
                   > cd ..; echo $cwd
                   /tmp/from

               here's the behavior with symlinks set to `chase',

                   > cd /tmp/to/dst; echo $cwd
                   /tmp/from/src
                   > cd ..; echo $cwd
                   /tmp/from

               here's the behavior with symlinks set to `ignore',

                   > cd /tmp/to/dst; echo $cwd
                   /tmp/to/dst
                   > cd ..; echo $cwd
                   /tmp/to

               and here's the behavior with symlinks set to `expand'.

                   > cd /tmp/to/dst; echo $cwd
                   /tmp/to/dst
                   > cd ..; echo $cwd
                   /tmp/to
                   > cd /tmp/to/dst; echo $cwd
                   /tmp/to/dst
                   > cd ".."; echo $cwd
                   /tmp/from
                   > /bin/echo ..
                   /tmp/to
                   > /bin/echo ".."
                   ..

               Note that `expand' expansion 1) works just like `ignore' for builtins like cd,  2)
               is prevented by quoting, and 3) happens before filenames are passed to non-builtin
               commands.

       tcsh (+)
               The version number of the shell in the format `R.VV.PP', where `R'  is  the  major
               release number, `VV' the current version and `PP' the patchlevel.

       term    The  terminal  type.   Usually  set  in  ~/.login  as  described under Startup and
               shutdown.

       time    If set to a number, then the time builtin (q.v.) executes automatically after each
               command  which  takes more than that many CPU seconds.  If there is a second word,
               it is used as a format string for  the  output  of  the  time  builtin.   (u)  The
               following sequences may be used in the format string:

               %U  The time the process spent in user mode in cpu seconds.
               %S  The time the process spent in kernel mode in cpu seconds.
               %E  The elapsed (wall clock) time in seconds.
               %P  The CPU percentage computed as (%U + %S) / %E.
               %W  Number of times the process was swapped.
               %X  The average amount in (shared) text space used in Kbytes.
               %D  The average amount in (unshared) data/stack space used in Kbytes.
               %K  The total space used (%X + %D) in Kbytes.
               %M  The maximum memory the process had in use at any time in Kbytes.
               %F  The number of major page faults (page needed to be brought from disk).
               %R  The number of minor page faults.
               %I  The number of input operations.
               %O  The number of output operations.
               %r  The number of socket messages received.
               %s  The number of socket messages sent.
               %k  The number of signals received.
               %w  The number of voluntary context switches (waits).
               %c  The number of involuntary context switches.

               Only  the first four sequences are supported on systems without BSD resource limit
               functions.  The default time format is `%Uu %Ss %E %P %X+%Dk %I+%Oio %Fpf+%Ww' for
               systems that support resource usage reporting and `%Uu %Ss %E %P' for systems that
               do not.

               Under Sequent's DYNIX/ptx, %X, %D, %K, %r  and  %s  are  not  available,  but  the
               following additional sequences are:

               %Y  The number of system calls performed.
               %Z  The number of pages which are zero-filled on demand.
               %i  The number of times a process's resident set size was increased by the kernel.
               %d  The number of times a process's resident set size was decreased by the kernel.
               %l  The number of read system calls performed.
               %m  The number of write system calls performed.
               %p  The number of reads from raw disk devices.
               %q  The number of writes to raw disk devices.

               and  the  default  time format is `%Uu %Ss %E %P %I+%Oio %Fpf+%Ww'.  Note that the
               CPU percentage can be higher than 100% on multi-processors.

       tperiod (+)
               The period, in minutes, between executions of the periodic special alias.

       tty (+) The name of the tty, or empty if not attached to one.

       uid (+) The user's real user ID.

       user    The user's login name.

       verbose If set, causes the words of each command to be printed, after history substitution
               (if any).  Set by the -v command line option.

       version (+)
               The  version ID stamp.  It contains the shell's version number (see tcsh), origin,
               release date, vendor,  operating  system  and  machine  (see  VENDOR,  OSTYPE  and
               MACHTYPE)  and  a  comma-separated list of options which were set at compile time.
               Options which are set by default in the distribution are noted.

               8b    The shell is eight bit clean; default
               7b    The shell is not eight bit clean
               wide  The shell is multibyte encoding clean (like UTF-8)
               nls   The system's NLS is used; default for systems with NLS
               lf    Login shells execute /etc/csh.login before instead of  after  /etc/csh.cshrc
                     and ~/.login before instead of after ~/.tcshrc and ~/.history.
               dl    `.' is put last in path for security; default
               nd    `.' is omitted from path for security
               vi    vi(1)-style editing is the default rather than emacs(1)-style
               dtr   Login shells drop DTR when exiting
               bye   bye is a synonym for logout and log is an alternate name for watchlog
               al    autologout is enabled; default
               kan   Kanji  is  used  if  appropriate  according  to  locale settings, unless the
                     nokanji shell variable is set
               sm    The system's malloc(3) is used
               hb    The `#!<program> <args>' convention is emulated when executing shell scripts
               ng    The newgrp builtin is available
               rh    The shell attempts to set the REMOTEHOST environment variable
               afs   The  shell  verifies  your  password  with  the  kerberos  server  if  local
                     authentication fails.  The afsuser shell variable or the AFSUSER environment
                     variable override your local username if set.

               An administrator may enter additional strings to indicate differences in the local
               version.

       vimode (+)
               If  unset,  various  key  bindings change behavior to be more emacs(1)-style: word
               boundaries are determined by wordchars versus other characters.

               If set, various  key  bindings  change  behavior  to  be  more  vi(1)-style:  word
               boundaries  are determined by wordchars versus whitespace versus other characters;
               cursor behavior depends upon current vi mode (command, delete, insert, replace).

               This variable is unset by bindkey -e  and  set  by  bindkey  -v.   vimode  may  be
               explicitly set or unset by the user after those bindkey operations if required.

       visiblebell (+)
               If set, a screen flash is used rather than the audible bell.  See also nobeep.

       watch (+)
               A list of user/terminal pairs to watch for logins and logouts.  If either the user
               is `any' all terminals are watched for the given user  and  vice  versa.   Setting
               watch to `(any any)' watches all users and terminals.  For example,

                   set watch = (george ttyd1 any console $user any)

               reports  activity  of  the  user  `george'  on ttyd1, any user on the console, and
               oneself (or a trespasser) on any terminal.

               Logins and logouts are checked every 10 minutes by default, but the first word  of
               watch can be set to a number to check every so many minutes.  For example,

                   set watch = (1 any any)

               reports  any  login/logout  once every minute.  For the impatient, the log builtin
               command triggers a watch report at any time.  All current logins are reported  (as
               with the log builtin) when watch is first set.

               The who shell variable controls the format of watch reports.

       who (+) The format string for watch messages.  The following sequences are replaced by the
               given information:

               %n  The name of the user who logged in/out.
               %a  The observed action, i.e., `logged on', `logged off' or `replaced olduser on'.
               %l  The terminal (tty) on which the user logged in/out.
               %M  The full hostname of the remote host, or `local' if the login/logout was  from
                   the local host.
               %m  The hostname of the remote host up to the first `.'.  The full name is printed
                   if it is an IP address or an X Window System display.

               %M and %m are available  on  only  systems  that  store  the  remote  hostname  in
               /etc/utmp.   If  unset,  `%n  has  %a  %l from %m.' is used, or `%n has %a %l.' on
               systems which don't store the remote hostname.

       wordchars (+)
               A list of non-alphanumeric characters to be considered  part  of  a  word  by  the
               forward-word, backward-word etc., editor commands.  If unset, the default value is
               determined based on the state of vimode: if vimode is unset, `*?_-.[]~='  is  used
               as the default; if vimode is set, `_' is used as the default.

ENVIRONMENT

       AFSUSER (+)
               Equivalent to the afsuser shell variable.

       COLUMNS The number of columns in the terminal.  See Terminal management.

       DISPLAY Used  by  X  Window  System (see X(1)).  If set, the shell does not set autologout
               (q.v.).

       EDITOR  The pathname to a default editor.  Used by the run-fg-editor editor command if the
               the editors shell variable is unset.  See also the VISUAL environment variable.

       GROUP (+)
               Equivalent to the group shell variable.

       HOME    Equivalent to the home shell variable.

       HOST (+)
               Initialized  to  the  name  of  the  machine  on  which  the  shell is running, as
               determined by the gethostname(2) system call.

       HOSTTYPE (+)
               Initialized to the type of machine on which the shell is running, as determined at
               compile time.  This variable is obsolete and will be removed in a future version.

       HPATH (+)
               A  colon-separated  list of directories in which the run-help editor command looks
               for command documentation.

       LANG    Gives the preferred character environment.  See Native Language System support.

       LC_CTYPE
               If set, only ctype character handling is  changed.   See  Native  Language  System
               support.

       LINES   The number of lines in the terminal.  See Terminal management.

       LS_COLORS
               The format of this variable is reminiscent of the termcap(5) file format; a colon-
               separated list of expressions of the  form  "xx=string",  where  "xx"  is  a  two-
               character variable name.  The variables with their associated defaults are:

                   no   0      Normal (non-filename) text
                   fi   0      Regular file
                   di   01;34  Directory
                   ln   01;36  Symbolic link
                   pi   33     Named pipe (FIFO)
                   so   01;35  Socket
                   do   01;35  Door
                   bd   01;33  Block device
                   cd   01;32  Character device
                   ex   01;32  Executable file
                   mi   (none) Missing file (defaults to fi)
                   or   (none) Orphaned symbolic link (defaults to ln)
                   lc   ^[[    Left code
                   rc   m      Right code
                   ec   (none) End code (replaces lc+no+rc)

               You need to include only the variables you want to change from the default.

               File  names  can also be colorized based on filename extension.  This is specified
               in the LS_COLORS variable using the syntax "*ext=string".  For example, using  ISO
               6429  codes, to color all C-language source files blue you would specify "*.c=34".
               This would color all files ending in .c in blue (34) color.

               Control characters can be  written  either  in  C-style-escaped  notation,  or  in
               stty-like  ^-notation.   The  C-style  notation adds ^[ for Escape, _ for a normal
               space character, and ? for Delete.  In addition, the ^[ escape  character  can  be
               used to override the default interpretation of ^[, ^, : and =.

               Each  file will be written as <lc> <color-code> <rc> <filename> <ec>.  If the <ec>
               code is undefined, the sequence <lc> <no> <rc> will  be  used  instead.   This  is
               generally more convenient to use, but less general.  The left, right and end codes
               are provided so you don't have to type common parts over and  over  again  and  to
               support  weird terminals; you will generally not need to change them at all unless
               your terminal does not use ISO 6429 color sequences but a different system.

               If your terminal does use ISO 6429 color codes, you can  compose  the  type  codes
               (i.e.,  all  except the lc, rc, and ec codes) from numerical commands separated by
               semicolons.  The most common commands are:

                       0   to restore default color
                       1   for brighter colors
                       4   for underlined text
                       5   for flashing text
                       30  for black foreground
                       31  for red foreground
                       32  for green foreground
                       33  for yellow (or brown) foreground
                       34  for blue foreground
                       35  for purple foreground
                       36  for cyan foreground
                       37  for white (or gray) foreground
                       40  for black background
                       41  for red background
                       42  for green background
                       43  for yellow (or brown) background
                       44  for blue background
                       45  for purple background
                       46  for cyan background
                       47  for white (or gray) background

               Not all commands will work on all systems or display devices.

               A few terminal programs do not recognize the default end code  properly.   If  all
               text  gets  colorized after you do a directory listing, try changing the no and fi
               codes from 0 to the numerical codes for your standard fore- and background colors.

       MACHTYPE (+)
               The machine type (microprocessor class or machine model), as determined at compile
               time.

       NOREBIND (+)
               If  set,  printable characters are not rebound to self-insert-command.  See Native
               Language System support.

       OSTYPE (+)
               The operating system, as determined at compile time.

       PATH    A  colon-separated  list  of  directories  in  which  to  look  for   executables.
               Equivalent to the path shell variable, but in a different format.

       PWD (+) Equivalent  to  the  cwd  shell variable, but not synchronized to it; updated only
               after an actual directory change.

       REMOTEHOST (+)
               The host from which the user has logged in remotely, if this is the case  and  the
               shell  is  able  to  determine it.  Set only if the shell was so compiled; see the
               version shell variable.

       SHLVL (+)
               Equivalent to the shlvl shell variable.

       SYSTYPE (+)
               The current system type.  (Domain/OS only)

       TERM    Equivalent to the term shell variable.

       TERMCAP The terminal capability string.  See Terminal management.

       USER    Equivalent to the user shell variable.

       VENDOR (+)
               The vendor, as determined at compile time.

       VISUAL  The pathname to a default full-screen editor.  Used by  the  run-fg-editor  editor
               command  if  the  the  editors  shell  variable  is  unset.   See  also the EDITOR
               environment variable.

FILES

       /etc/csh.cshrc  Read first by every shell.  ConvexOS, Stellix and Intel use /etc/cshrc and
                       NeXTs use /etc/cshrc.std.  A/UX, AMIX, Cray and IRIX have no equivalent in
                       csh(1), but read this file in tcsh anyway.  Solaris 2.x does not  have  it
                       either, but tcsh reads /etc/.cshrc.  (+)
       /etc/csh.login  Read  by  login  shells after /etc/csh.cshrc.  ConvexOS, Stellix and Intel
                       use /etc/login, NeXTs use /etc/login.std, Solaris 2.x uses /etc/.login and
                       A/UX, AMIX, Cray and IRIX use /etc/cshrc.
       ~/.tcshrc (+)   Read by every shell after /etc/csh.cshrc or its equivalent.
       ~/.cshrc        Read  by  every shell, if ~/.tcshrc doesn't exist, after /etc/csh.cshrc or
                       its equivalent.  This manual uses `~/.tcshrc' to mean  `~/.tcshrc  or,  if
                       ~/.tcshrc is not found, ~/.cshrc'.
       ~/.history      Read  by  login  shells  after  ~/.tcshrc if savehist is set, but see also
                       histfile.
       ~/.login        Read by login shells after ~/.tcshrc or  ~/.history.   The  shell  may  be
                       compiled   to   read  ~/.login  before  instead  of  after  ~/.tcshrc  and
                       ~/.history; see the version shell variable.
       ~/.cshdirs (+)  Read by login shells after ~/.login if  savedirs  is  set,  but  see  also
                       dirsfile.
       /etc/csh.logout Read  by  login  shells  at  logout.   ConvexOS,  Stellix  and  Intel  use
                       /etc/logout and NeXTs use /etc/logout.std.  A/UX, AMIX, Cray and IRIX have
                       no  equivalent  in csh(1), but read this file in tcsh anyway.  Solaris 2.x
                       does not have it either, but tcsh reads /etc/.logout.  (+)
       ~/.logout       Read by login shells at logout after /etc/csh.logout or its equivalent.
       /bin/sh         Used to interpret shell scripts not starting with a `#'.
       /tmp/sh*        Temporary file for `<<'.
       /etc/passwd     Source of home directories for `~name' substitutions.

       The order in which startup files are read may differ if the shell  was  so  compiled;  see
       Startup and shutdown and the version shell variable.

NEW FEATURES (+)

       This  manual  describes tcsh as a single entity, but experienced csh(1) users will want to
       pay special attention to tcsh's new features.

       A command-line editor, which supports emacs(1)-style or vi(1)-style key bindings.  See The
       command-line editor and Editor commands.

       Programmable, interactive word completion and listing.  See Completion and listing and the
       complete and uncomplete builtin commands.

       Spelling correction (q.v.) of filenames, commands and variables.

       Editor commands (q.v.) which perform  other  useful  functions  in  the  middle  of  typed
       commands,  including  documentation  lookup  (run-help),  quick editor restarting (run-fg-
       editor) and command resolution (which-command).

       An enhanced history mechanism.  Events in the history list are time-stamped.  See also the
       history  command and its associated shell variables, the previously undocumented `#' event
       specifier and new modifiers under History substitution, the  *-history,  history-search-*,
       i-search-*,  vi-search-*  and toggle-literal-history editor commands and the histlit shell
       variable.

       Enhanced directory parsing and directory stack handling.  See the cd, pushd, popd and dirs
       commands  and  their  associated  shell  variables,  the  description  of  Directory stack
       substitution, the dirstack, owd and symlinks shell variables and the normalize-command and
       normalize-path editor commands.

       Negation in glob-patterns.  See Filename substitution.

       New File inquiry operators (q.v.) and a filetest builtin which uses them.

       A  variety  of  Automatic,  periodic  and  timed events (q.v.) including scheduled events,
       special aliases, automatic logout and terminal locking, command timing  and  watching  for
       logins and logouts.

       Support  for  the  Native Language System (see Native Language System support), OS variant
       features (see OS variant support and the echo_style shell variable)  and  system-dependent
       file locations (see FILES).

       Extensive terminal-management capabilities.  See Terminal management.

       New  builtin  commands  including  builtins,  hup, ls-F, newgrp, printenv, which and where
       (q.v.).

       New variables that make useful information easily available to the shell.   See  the  gid,
       loginsh,  oid, shlvl, tcsh, tty, uid and version shell variables and the HOST, REMOTEHOST,
       VENDOR, OSTYPE and MACHTYPE environment variables.

       A new syntax for including useful information in  the  prompt  string  (see  prompt),  and
       special prompts for loops and spelling correction (see prompt2 and prompt3).

       Read-only variables.  See Variable substitution.

BUGS

       When  a  suspended  command  is restarted, the shell prints the directory it started in if
       this is different from the current directory.  This can be misleading (i.e., wrong) as the
       job may have changed directories internally.

       Shell builtin functions are not stoppable/restartable.  Command sequences of the form `a ;
       b ; c' are also not handled gracefully when stopping is attempted.  If  you  suspend  `b',
       the  shell  will  then  immediately  execute  `c'.   This is especially noticeable if this
       expansion results from an alias.  It suffices to place the sequence of commands in ()'s to
       force it to a subshell, i.e., `( a ; b ; c )'.

       Control  over  tty  output  after  processes  are  started is primitive; perhaps this will
       inspire someone to work on a good virtual  terminal  interface.   In  a  virtual  terminal
       interface much more interesting things could be done with output control.

       Alias  substitution  is  most  often  used  to  clumsily  simulate shell procedures; shell
       procedures should be provided rather than aliases.

       Control structures should be parsed rather than being  recognized  as  built-in  commands.
       This  would  allow control commands to be placed anywhere, to be combined with `|', and to
       be used with `&' and `;' metasyntax.

       foreach doesn't ignore here documents when looking for its end.

       It should be possible to use the `:' modifiers on the output of command substitutions.

       The screen update for lines longer than the screen width is  very  poor  if  the  terminal
       cannot move the cursor up (i.e., terminal type `dumb').

       HPATH and NOREBIND don't need to be environment variables.

       Glob-patterns  which  do not use `?', `*' or `[]' or which use `{}' or `~' are not negated
       correctly.

       The single-command form of if does output redirection even if the expression is false  and
       the command is not executed.

       ls-F  includes  file  identification characters when sorting filenames and does not handle
       control characters in filenames well.  It cannot be interrupted.

       Command substitution supports multiple commands and conditions, but not cycles or backward
       gotos.

       Report  bugs  at http://bugs.gw.com/, preferably with fixes.  If you want to help maintain
       and test tcsh, send mail to tcsh-request@mx.gw.com with the text  `subscribe  tcsh'  on  a
       line by itself in the body.

THE T IN TCSH

       In  1964,  DEC  produced the PDP-6.  The PDP-10 was a later re-implementation.  It was re-
       christened the DECsystem-10 in 1970 or so when DEC brought out the second model, the KI10.

       TENEX was created at Bolt, Beranek & Newman (a Cambridge,  Massachusetts  think  tank)  in
       1972  as an experiment in demand-paged virtual memory operating systems.  They built a new
       pager for the DEC PDP-10 and created the OS to go with it.  It was extremely successful in
       academia.

       In 1975, DEC brought out a new model of the PDP-10, the KL10; they intended to have only a
       version of TENEX, which they had licensed from BBN, for the new box.   They  called  their
       version  TOPS-20  (their  capitalization  is  trademarked).   A lot of TOPS-10 users (`The
       OPerating  System  for  PDP-10')  objected;  thus  DEC  found  themselves  supporting  two
       incompatible systems on the same hardware--but then there were 6 on the PDP-11!

       TENEX,  and  TOPS-20 to version 3, had command completion via a user-code-level subroutine
       library called ULTCMD.  With version 3, DEC moved all that capability and  more  into  the
       monitor  (`kernel'  for  you  Unix  types),  accessed by the COMND% JSYS (`Jump to SYStem'
       instruction, the supervisor call mechanism [are my IBM roots also showing?]).

       The creator of tcsh was impressed by this feature and several others of TENEX and TOPS-20,
       and created a version of csh which mimicked them.

LIMITATIONS

       The system limits argument lists to ARG_MAX characters.

       The number of arguments to a command which involves filename expansion is limited to 1/6th
       the number of characters allowed in an argument list.

       Command substitutions may substitute no more characters than are allowed  in  an  argument
       list.

       To  detect looping, the shell restricts the number of alias substitutions on a single line
       to 20.

SEE ALSO

       csh(1), emacs(1), ls(1), newgrp(1), sh(1), setpath(1),  stty(1),  su(1),  tset(1),  vi(1),
       x(1), access(2), execve(2), fork(2), killpg(2), pipe(2), setrlimit(2), sigvec(2), stat(2),
       umask(2),  vfork(2),  wait(2),  malloc(3),  setlocale(3),  tty(4),  a.out(5),  termcap(5),
       environ(7), termio(7), Introduction to the C Shell

VERSION

       This manual documents tcsh 6.20.00 (Astron) 2016-11-24.

AUTHORS

       William Joy
         Original author of csh(1)
       J.E. Kulp, IIASA, Laxenburg, Austria
         Job control and directory stack features
       Ken Greer, HP Labs, 1981
         File name completion
       Mike Ellis, Fairchild, 1983
         Command name recognition/completion
       Paul Placeway, Ohio State CIS Dept., 1983-1993
         Command line editor, prompt routines, new glob syntax and numerous fixes and speedups
       Karl Kleinpaste, CCI 1983-4
         Special aliases, directory stack extraction stuff, login/logout watch, scheduled events,
         and the idea of the new prompt format
       Rayan Zachariassen, University of Toronto, 1984
         ls-F and which builtins and numerous bug fixes, modifications and speedups
       Chris Kingsley, Caltech
         Fast storage allocator routines
       Chris Grevstad, TRW, 1987
         Incorporated 4.3BSD csh into tcsh
       Christos S. Zoulas, Cornell U. EE Dept., 1987-94
         Ports to HPUX, SVR2 and SVR3, a SysV version of getwd.c, SHORT_STRINGS support and a new
         version of sh.glob.c
       James J Dempsey, BBN, and Paul Placeway, OSU, 1988
         A/UX port
       Daniel Long, NNSC, 1988
         wordchars
       Patrick Wolfe, Kuck and Associates, Inc., 1988
         vi mode cleanup
       David C Lawrence, Rensselaer Polytechnic Institute, 1989
         autolist and ambiguous completion listing
       Alec Wolman, DEC, 1989
         Newlines in the prompt
       Matt Landau, BBN, 1989
         ~/.tcshrc
       Ray Moody, Purdue Physics, 1989
         Magic space bar history expansion
       Mordechai ????, Intel, 1989
         printprompt() fixes and additions
       Kazuhiro Honda, Dept. of Computer Science, Keio University, 1989
         Automatic spelling correction and prompt3
       Per Hedeland, Ellemtel, Sweden, 1990-
         Various bugfixes, improvements and manual updates
       Hans J. Albertsson (Sun Sweden)
         ampm, settc and telltc
       Michael Bloom
         Interrupt handling fixes
       Michael Fine, Digital Equipment Corp
         Extended key support
       Eric Schnoebelen, Convex, 1990
         Convex support, lots of csh bug fixes, save and restore of directory stack
       Ron Flax, Apple, 1990
         A/UX 2.0 (re)port
       Dan Oscarsson, LTH Sweden, 1990
         NLS support and simulated NLS support for non NLS sites, fixes
       Johan Widen, SICS Sweden, 1990
         shlvl, Mach support, correct-line, 8-bit printing
       Matt Day, Sanyo Icon, 1990
         POSIX termio support, SysV limit fixes
       Jaap Vermeulen, Sequent, 1990-91
         Vi mode fixes, expand-line, window change fixes, Symmetry port
       Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
         autolist  beeping  options,  modified  the history search to search for the whole string
         from the beginning of the line to the cursor.
       Scott Krotz, Motorola, 1991
         Minix port
       David Dawes, Sydney U. Australia, Physics Dept., 1991
         SVR4 job control fixes
       Jose Sousa, Interactive Systems Corp., 1991
         Extended vi fixes and vi delete command
       Marc Horowitz, MIT, 1991
         ANSIfication fixes, new exec hashing code, imake fixes, where
       Bruce Sterling Woodcock, sterling@netcom.com, 1991-1995
         ETA and Pyramid port, Makefile and lint fixes, ignoreeof=n addition, and  various  other
         portability changes and bug fixes
       Jeff Fink, 1992
         complete-word-fwd and complete-word-back
       Harry C. Pulley, 1992
         Coherent port
       Andy Phillips, Mullard Space Science Lab U.K., 1992
         VMS-POSIX port
       Beto Appleton, IBM Corp., 1992
         Walking process group fixes, csh bug fixes, POSIX file tests, POSIX SIGHUP
       Scott Bolte, Cray Computer Corp., 1992
         CSOS port
       Kaveh R. Ghazi, Rutgers University, 1992
         Tek, m88k, Titan and Masscomp ports and fixes.  Added autoconf support.
       Mark Linderman, Cornell University, 1992
         OS/2 port
       Mika Liljeberg, liljeber@kruuna.Helsinki.FI, 1992
         Linux port
       Tim P. Starrin, NASA Langley Research Center Operations, 1993
         Read-only variables
       Dave Schweisguth, Yale University, 1993-4
         New man page and tcsh.man2html
       Larry Schwimmer, Stanford University, 1993
         AFS and HESIOD patches
       Luke Mewburn, RMIT University, 1994-6
         Enhanced directory printing in prompt, added ellipsis and rprompt.
       Edward Hutchins, Silicon Graphics Inc., 1996
         Added implicit cd.
       Martin Kraemer, 1997
         Ported to Siemens Nixdorf EBCDIC machine
       Amol Deshpande, Microsoft, 1997
         Ported  to  WIN32 (Windows/95 and Windows/NT); wrote all the missing library and message
         catalog code to interface to Windows.
       Taga Nayuta, 1998
         Color ls additions.

THANKS TO

       Bryan Dunlap, Clayton Elwell, Karl Kleinpaste, Bob Manson, Steve  Romig,  Diana  Smetters,
       Bob  Sutterfield, Mark Verber, Elizabeth Zwicky and all the other people at Ohio State for
       suggestions and encouragement

       All the people on the net, for putting up with, reporting  bugs  in,  and  suggesting  new
       additions to each and every version

       Richard M. Alderson III, for writing the `T in tcsh' section