Provided by: rlwrap_0.43-1build3_amd64 
NAME
rlwrap - readline wrapper
SYNOPSIS
rlwrap [rlwrap-options] command ...
DESCRIPTION
rlwrap runs the specified command, intercepting user input in order to provide readline's
line editing, persistent history and completion.
rlwrap tries (and almost succeeds) to be completely transparent - you (or your shell)
shouldn't notice any difference between command and rlwrap command - except the added
readline functionality, of course. This should even hold true when you are re-directing,
piping and sending signals from and to command, and when command manipulates its terminal
settings or working directory.
There are many options to add (programmable) completion, handle multi-line input, colour
and re-write prompts. If you don't need them (and you probably don't), you can skip the
rest of this manpage.
OPTIONS
-a, --always-readline [password_prompt]
Always remain in "readline mode", regardless of command's terminal settings. Use
this option if you want to use rlwrap with commands that already do some line
editing. NB: With this option, rlwrap will echo (and save) passwords, unless you
give command's password prompt as an argument. The argument is optional; if given,
it has to directly follow the option without an intervening space.
On a linux machine you can use the -N (--no-children) option to avoid wrapping
pagers and editors called from command; this should make them much more usable
Many commands that need --always-readline may also need -t dumb to prevent terminal
control sequences from confusing rlwrap (although this will annoy the
above-mentioned pagers and editors)
-A, --ansi-colour-aware
Prompts that use colour will confuse rlwrap, especially at the end of long input
lines. This option will make rlwrap better behaved in such cases. If the prompt
contains anything fancier than ANSI colour codes, this option may actually make
things worse.
-b, --break-chars list_of_characters
Consider the specified characters word-breaking (whitespace is always
word-breaking). This determines what is considered a "word", both when completing
and when building a completion word list from files specified by -f options
following (not preceding!) it. Default list (){}[],'+-=&^%$#@"";|\ Unless -c is
specified, / and . (period) are included in the default list.
-c, --complete-filenames
Complete filenames (filename completion is always case-sensitive, even with the -i
option). On Linux, OS X, FreeBSD and Solaris rlwrap will keep track of command's
working directory, so that relative filenames will be completed as one would
expect.
-C, --command-name command_name|N
Use command_name instead of command to determine the names of history and
completion files, and to initialise readline (as specified in ~/.inputrc). A
numeric argument N > 0 means: use the Nth argument counting backwards from the end
of the argument list
-D, --history-no-dupes n
How aggressively to weed out duplicate entries from the input history. If n = 0,
all inputs are kept in the history list, if n = 1 (this is the default) consecutive
duplicates are dropped from the list, while n = 2 will make rlwrap drop all
previous occurrences of the current input from the list.
-e, --extra-char-after-completion char
By default, rlwrap appends a space after any inserted completion text. Use this
option to change this to '' (don't insert anything) or some other character.
-f, --file file
Split file into words (using the default word-breaking characters, or those
specified by --break-chars), and add them to the completion word list. This option
can be given more than once, and adds to the default completion list in
$RLWRAP_HOME or /usr/share/rlwrap/completions.
Specifying -f . will make rlwrap use the current history file as a completion word
list.
-g, --forget-matching regexp
Forget (i.e. never put into the history list) all input lines that match the POSIX
1003.2 regular expression regexp. The match is always case-insensitive. regexp may
be an ordinary string. For more about regular expressions, see regex (7)
-h, --help
Print a short help message.
-H, --history-filename file
Read command history from file (and write it back there if --histsize >= 0)
-i, --case-insensitive
Ignore case when completing (filename completion remains case-sensitive). This
option has to come before any -f options.
-I, --pass-sigint-as-sigterm
Send a TERM signal to command when an INT is received (e.g. when you press CTRL-C).
-l, --logfile file
When in readline mode, append command's output (including echo'ed user input) to
file (creating file when it doesn't exist).
-n, --no-warnings
Don't print warnings.
-N, --no-children
Don't rlwrap command's children: whenever rlwrap notices that command is waiting
for one of its children, it switches to direct mode, handing down all keypresses
immediately. With this option commands that need --always-readline can call
editors and pagers and still be usable.
This option needs /proc/command_pid/wchan, so it only works with linux kernels
configured with CONFIG_KALLSYMS.
-m, --multi-line [newline_substitute]
Enable multi-line input using a "newline substitute" character sequence (" \ ",
[space-backslash-space] by default). Newline substitutes are translated to newlines
before sending the input to command. With this option, you can call an external
editor $RLWRAP_EDITOR on the (expanded) current input with the rlwrap_call_editor
key (CTRL-^ by default) The argument is optional; if given, it has to directly
follow the option without an intervening space.
-M, --multi-line-ext .ext
Call multi-line-editor on temporary files with filename extension .ext (useful for
e.g. automatic syntax colouring)
-o, --one-shot
Send an EOF to command after accepting the first line of input
-O, --only-cook regexp
Only ever "cook" prompts that match regexp
-p, --prompt-colour [colour_name|Colour_name|colour_spec]
Use one of the colour names black, red, green, yellow, blue, cyan, purple
(=magenta) or white, or an ANSI-conformant <colour_spec> to colour any prompt
displayed by command. An uppercase colour name (Yellow or YELLOW ) gives a bold
prompt. Prompts that already contain (colour) escape sequences or one of the
readline "ignore markers" (ASCII 0x01 and 0x02) are not coloured. This option
implies --ansi-colour-aware. colour spec has the form <attr>;<fg>[;<bg>] Example:
-p'1;31' will give a bold red prompt on the current background (this is the default
when no argument is given). Google for 'ANSI color' to learn more about colour
codes. The argument is optional; if given, it has to directly follow the option
without an intervening space.
-P, --pre-given text
Start rlwrap with text in its edit buffer (this will automatically set the
--always-readline option).
-q, --quote-characters list_of_characters
Assume that the given characters act as quotes, e.g. when matching parentheses.
Take care to escape the list properly for your shell (example: -q "\"'", which
happens to be the default, or -q "\"" which will be better for lisp-like input)
-r, --remember
Put all words seen on in- and output on the completion list.
-R, --renice
Make rlwrap nicer than command (cf nice (1)). This may prevent rlwrap from
interrupting command to display a prompt when command is still "thinking" about
what to output next.
-s, --histsize N
Limit the history list to N entries, truncating the history file (default: 300). A
negative size -N (even -0) means the same as N, but treats the history file as
read-only.
-S, --substitute-prompt prompt
Substitute the specified prompt for command's own prompt. Mainly useful when
command doesn't have a prompt.
-t, --set-term-name name
Set command's TERM to name. Programs that confuse rlwrap with fancy screen control
codes can sometimes be tamed by specifying -t dumb
-U, --mirror-arguments
(linux only) Keep track of command's arguments as seen by the ps (1) command, and
mirror them in rlwrap's own arguments This is mainly useful for commands that
overwrite command-line password arguments that would be exposed by rlwrap without
this option.
-v, --version
Print rlwrap version.
-w, --wait-before-prompt timeout
In order to determine if command's last output is a prompt, rlwrap waits timeout
milliseconds after receiving it. Only when no more output has arrived, it is
cooked (coloured, filtered and/or replaced by a substitute prompt) and displayed as
a prompt. Before this the prompt is displayed "uncooked". Most users won't notice,
but heavy cookers can prepend the timeout with a minus sign, making rlwrap hold
back the prompt until it has been cooked ("patient mode"). This will prevent
flashing of the prompt, but it will also interfere with long output lines and make
switches from direct to readline mode less reliable. Default timeout: 40 ms
-W, --polling
EXPERIMENTAL: Wake up every timeout millisecs, where timeout is the same as for the
-w (--wait-before-prompt) option, 40 ms by default. This is used to sense the
slave's interrupt character and ISIG flag and to adjust stdin's terminal settings
accordingly, even before you press a key. Try this option e.g. when CTRL-C acts
differently on command with, and without, rlwrap.
-z, --filter filter
Use a filter to change rlwrap's behaviour. A filter can be used to keep certain
input out of the history, to change the prompt, to implement simple macros or
programmable completion.. rlwrap comes with a perl and a Python 3 module to make
filter writing easy. (cf. RlwrapFilter(3pm) for the perl module, the python one is
very similar) A number of example filters are installed in the directory
/usr/share/rlwrap/filters. "rlwrap -z filter" displays information about a filter,
"rlwrap -z listing" lists all currently installed filters. If filter needs
arguments, you should quote the whole filter command line:
rlwrap -z 'filter args' command ...
rlwrap -z 'pipeline filter1 ... : filter2 ... : ...' command ...
If this command line contains shell metacharacters, rlwrap passes it to the system
shell for parsing.
EXAMPLES
Run nc (netcat) with command-line editing and history
rlwrap nc
Wrap smbclient (which uses readline itself), keep passwords out of the history and don't
wrap commands launched from smbclient (like more)
rlwrap -aPassword: -N smbclient //PEANUT/C
Wrap gauche (a Scheme interpreter) with a bold blue prompt, enable multi-line editing
(using .scm as filename extension) and don't consider single quotes as quotes (so that the
parentheses in e.g. (print 'q) match)
rlwrap -pBlue -m -M .scm -q'
Get a list of all currently installed filters
rlwrap -z listing
Get help for the filter pipeto
rlwrap -z pipeto
Wrap sqlite3, use the pipeto filter to be able to pipe the output of SQL commands through
grep and/or less, complete (case-insensitively) on the SQL keywords in 'sql_words'
rlwrap -a -z pipeto -i -f sql_words sqlite3 contacts.db
In a shell script, use rlwrap in 'one-shot' mode as a replacement for read
order=$(rlwrap -pYellow -S 'Your pizza? ' -H past_orders -P Margherita -o cat)
DIRECT MODE AND READLINE MODE
Most simple console commands put your terminal either in "cooked" or in "raw" mode. In
cooked mode the terminal will wait until you press the ENTER key before handing the entire
line to the program, in raw mode every key you press is handed down immediately. In cooked
mode you generally can use the backspace key, but not the arrow keys, to edit your input.
Most simple console commands use cooked mode whenever they want whole input lines, and raw
mode when they want single keypresses. More sophisticated commands tend to use raw mode
all the time; they may sometimes be rlwrappable with the -a (and -N) options.
When you rlwrap command, rlwrap will run it a in a separate session, under its own
(controlling) "pseudo-terminal" (pty), and monitor this pty to see whether it is in raw,
or in cooked mode. In the first case, rlwrap will copy all input and output directly
between command and your terminal ("direct mode"). In the second case, rlwrap will use
readline to edit your input ("readline mode"), and monitor command's output - every last
line that doesn't end with a newline is a potential prompt. How it handles such a
candidate prompt depends on its being in "patient" or "impatient" mode:
PATIENT AND IMPATIENT MODE
If command writes a lot of output, it tends to be written (and read) in "chunks". Not all
chunks will end with a newline, and we need to distinguish their last lines from real
prompts, especially if we want to re-write ("cook") prompts. rlwrap solves this (almost)
by waiting a little, to see if there is more to come. "A little" is 40 msec by default,
but this can be changed with the -w option. Normally rlwrap writes the suspected prompt
as soon as it is received, replacing it with a "cooked" version after the wait time. This
is called "impatient" mode. If you don't like the flashing effect (which can become
annoying when you "cook" the prompt heavily) you can put rlwrap in "patient mode" by
specifying a negative value with -w (e.g. -w -40). Rlwrap will then hold back the prompt
and only print if after cooking.
COOKING PROMPTS
If and when rlwrap decides that it has a prompt, it will perform a number of actions on
it, depending on the given options: filtering (-z), substituting (-S) and colouring (-p),
in this order. The resulting "cooked" prompt is then printed (after erasing the "raw"
prompt, if necessary)
SPECIAL KEYS AND BINDABLE COMMANDS
Control + O
Accept the current line, but don't put it in the history list. This action has a
readline command name rlwrap-accept-line-and-forget
Control + ^
Use an external editor (see RLWRAP_EDITOR below) to edit the current input (this
will only work if the -m option is set). This action has a readline command name
rlwrap-call-editor
(Not currently bound)
Any key can be bound to the readline command rlwrap-direct-keypress. This key will
then always be sent directly to command, even when rlwrap is not in direct mode.
(Not currently bound)
Any key can be bound to the readline command rlwrap-hotkey. This key will then
cause the current input line and the current history to be filtered (cf.
RlwrapFilter(3pm)) through the current filter (hence be a no-op when there is no
filter), which then can re-write the input line, move the cursor and update the
history. After that, the user can still edit the resulting input.
(Not currently bound)
rlwrap-hotkey-without-history acts like rlwrap-hotkey, but the history (which can
be quite large) is not passed to the filter. This is more efficient if the filter
wouldn't do anything useful with the history anyway.
The special keys were chosen for no other reason than that they are not currently bound
to any readline action. If you don't like them, (or your window manager swallows them)
they (and the other 3 commands) can be re-bound more sensibly by including lines like the
following in your ~/.inputrc:
"\M-\C-m": rlwrap-accept-line-and-forget # ESC-ENTER to accept but keep out of history
"\C-xe": rlwrap-call-editor # CTRL-x e to edit (multi-line) input in editor of your choice
$if erl # (only) for the Erlang shell:
"\C-g": rlwrap-direct-keypress # pass CTRL-g directly to enter 'user switch' command
$endif
"\C-y": rlwrap-hotkey-without-history # CTRL-y to filter input line (and e.g. insert X selection)
cf. the readline(3) manpage. (NB: take care to not use keys that are already caught by the
terminal driver, like CTRL+S, as rlwrap will never see those)
ENVIRONMENT
RLWRAP_HOME:
directory in which the history and completion files are kept.
RLWRAP_EDITOR (or else EDITOR, or else VISUAL):
editor to use for multi-line input (and rlwrap-edit-history). Example:
export RLWRAP_EDITOR="vi +%L"
export RLWRAP_EDITOR="vim '+call cursor(%L,%C)'"
export RLWRAP_EDITOR="emacs +%L:%C %F"
The first example above is the default; %L and %C are replaced by line and column numbers
corresponding to the cursor position in rlwrap's edit buffer, %F is replaced by name of
the (temporary) file. If %F is not used, this name is put after the (expanded)
$RLWAP_EDITOR
RLWRAP_FILTERDIR:
Any executable along your PATH can in theory be used as a filter, but because
filters have to follow a rather outlandish protocol (cf. RlwrapFilter (3)) it is a
good idea to keep them separate. This is why rlwrap adds a special filter directory
in front of $PATH just before launching a filter. By default, this is
/usr/share/rlwrap/filters, but $RLWRAP_FILTERDIR is used if set.
SIGNALS
A number of signals are forwarded to command: HUP INT QUIT USR1 USR2 TERM and (by way of
resizing command's terminal) WINCH. Some care is taken to handle TSTP (usually a result of
a CTRL-Z from the terminal) sensibly - for example, after suspending rlwrap in the middle
of a line edit, continuing (by typing 'fg') will land you at the exact spot where you
suspended it.
Filters that take more than 1 second to respond can be interrupted by a CTRL-C from the
terminal (although rlwrap will not survive this)
If command changes the keystrokes that send a particular signal from the keyboard (like
emacs, which uses CTRL-G instead of CTRL-C) rlwrap will do the same (but only after the
next keystroke - use the --polling option to make rlwrap more transparent in this respect)
When command is killed by a signal, rlwrap will clean up, reset its signal handlers an
then commit suicide by sending the same signal to itself. This means that your shell sees
the same exit status as it would have seen without rlwrap.
REDIRECTION
When the standard input is not a terminal, editing input doesn't make sense, so rlwrap
will ignore all options and simply execute command. When stdout (or stderr) is not a
terminal, rlwrap will re-open it to /dev/tty (the users terminal) after it has started
command, so that command's output is redirected as expected, but keyboard input and
rlwrap error messages are still visible.
The upshot of this is that rlwrap command behaves more or less like command when
redirecting.
EXIT STATUS
non-zero after a rlwrap error, or else command's exit status. rlwrap will always leave the
terminal in a tidy state, even after a crash.
FILES
rlwrap expects its history and completion files in $RLWRAP_HOME, but uses .dotfiles in the
user's home directory if this variable is not set. This will quickly become messy if you
use rlwrap for many different commands.
$RLWRAP_HOME/command_history, ~/.command_history
History for command (remember that command may be overridden by the --command-name
(or -C) option)
$RLWRAP_HOME/command_completions, ~/.command_completions
Per-user completion word list for command. rlwrap never writes into this list, but
one can combine -l and -f options to to simulate the effect of a -r option that
works across invocations.
/usr/share/rlwrap/completions/command
System-wide completion word list for command. This file is only consulted if the
per-user completion word list is not found.
$INPUTRC, ~/.inputrc
Individual readline initialisation file (See readline (3) for its format). rlwrap
sets its application name to command (this can be overridden by the -C option),
enabling different behaviours for different commands. One could e.g. put the
following lines in ~/.inputrc:
$if coqtop
set show-all-if-ambiguous On
$endif
making rlwrap show all completions whenever it runs coqtop
BUGS and LIMITATIONS
Though it is flexible, delivers the goods (readline functionality), and adheres to the
Unix "many small tools" paradigm, rlwrap is a kludge. It cannot know anything about
command's internal state, which makes context-sensitive completion impossible. Using the
readline library from within command is still the best option.
Also, because "it takes two to tango" there is no way for rlwrap to synchronise its
internal state with command, resulting in a number of subtle race conditions, where e.g.
command may have changed the state of its terminal before rlwrap has read command output
that was written before the state change. You will notice these races especially on a busy
machine and with heavy "cooking" and filtering, when suddenly (and unpredictably) promtps
or command output are garbled or incorrectly coloured.
rlwrap can try, but often fails to, handle prompts that contain control characters. A
filter may be used to clean up the prompt.
VERSION
This manpage documents rlwrap version 0.43
AUTHORS
The readline library (written by Brian Fox and Chet Ramey) does all the hard work behind
the scenes, the pty-handling code has been taken practically unchanged from rxvt-2.7.10
(currently maintained by Geoff C. Wing), and completion word lists are managed by Damian
Ivereigh's libredblack library. The few remaining lines of code were written by Hans Lub
(hanslub42@gmail.com).
SEE ALSO
readline(3), RlwrapFilter(3pm)
July 19, 2016 rlwrap(1)