xenial (1) original-awk.1.gz

Provided by: original-awk_2012-12-20-5_amd64 bug

NAME

       original-awk - pattern-directed scanning and processing language

SYNOPSIS

       original-awk [ -F fs ] [ -v var=value ] [ 'prog' | -f progfile ] [ file ...  ]

DESCRIPTION

       Awk  (original-awk)  scans  each  input  file  for  lines  that  match any of a set of patterns specified
       literally in prog or in one or more files specified as -f progfile.  With each pattern there  can  be  an
       associated action that will be performed when a line of a file matches the pattern.  Each line is matched
       against the pattern portion of every pattern-action statement; the associated  action  is  performed  for
       each  matched  pattern.   The  file  name  - means the standard input.  Any file of the form var=value is
       treated as an assignment, not a filename, and is executed at the time it would have  been  opened  if  it
       were  a  filename.   The  option  -v  followed  by  var=value  is an assignment to be done before prog is
       executed; any number of -v options may be present.  The -F fs option defines the input field separator to
       be the regular expression fs.

       An  input  line is normally made up of fields separated by white space, or by regular expression FS.  The
       fields are denoted $1, $2, ..., while $0 refers to the entire line.  If FS is null,  the  input  line  is
       split into one field per character.

       A pattern-action statement has the form

              pattern { action }

       A  missing  { action } means print the line; a missing pattern always matches.  Pattern-action statements
       are separated by newlines or semicolons.

       An action is a sequence of statements.  A statement can be one of the following:

              if( expression ) statement [ else statement ]
              while( expression ) statement
              for( expression ; expression ; expression ) statement
              for( var in array ) statement
              do statement while( expression )
              break
              continue
              { [ statement ... ] }
              expression              # commonly var = expression
              print [ expression-list ] [ > expression ]
              printf format [ , expression-list ] [ > expression ]
              return [ expression ]
              next                    # skip remaining patterns on this input line
              nextfile                # skip rest of this file, open next, start at top
              delete array[ expression ]# delete an array element
              delete array            # delete all elements of array
              exit [ expression ]     # exit immediately; status is expression

       Statements are terminated by semicolons, newlines or right braces.  An empty expression-list  stands  for
       $0.   String  constants  are quoted " ", with the usual C escapes recognized within.  Expressions take on
       string or numeric values as appropriate, and are built using the operators + - * / % ^  (exponentiation),
       and concatenation (indicated by white space).  The operators ! ++ -- += -= *= /= %= ^= > >= < <= == != ?:
       are also available in expressions.  Variables may be scalars, array elements (denoted  x[i])  or  fields.
       Variables  are  initialized  to  the  null  string.   Array subscripts may be any string, not necessarily
       numeric; this allows for a  form  of  associative  memory.   Multiple  subscripts  such  as  [i,j,k]  are
       permitted; the constituents are concatenated, separated by the value of SUBSEP.

       The  print  statement  prints  its  arguments  on the standard output (or on a file if >file or >>file is
       present or on a pipe if |cmd is present), separated by the current output field separator, and terminated
       by  the  output  record  separator.   file  and  cmd  may  be literal names or parenthesized expressions;
       identical string values in different statements denote the same open file.  The printf statement  formats
       its  expression  list  according to the format (see printf(3)).  The built-in function close(expr) closes
       the file or pipe expr.  The built-in function fflush(expr) flushes any buffered output for  the  file  or
       pipe expr.

       The mathematical functions exp, log, sqrt, sin, cos, and atan2 are built in.  Other built-in functions:

       length the length of its argument taken as a string, or of $0 if no argument.

       rand   random number on (0,1)

       srand  sets seed for rand and returns the previous seed.

       int    truncates to an integer value

       substr(s, m, n)
              the n-character substring of s that begins at position m counted from 1.

       index(s, t)
              the position in s where the string t occurs, or 0 if it does not.

       match(s, r)
              the  position  in  s  where  the  regular expression r occurs, or 0 if it does not.  The variables
              RSTART and RLENGTH are set to the position and length of the matched string.

       split(s, a, fs)
              splits the string s into array elements a[1], a[2], ..., a[n], and returns n.  The  separation  is
              done  with  the regular expression fs or with the field separator FS if fs is not given.  An empty
              string as field separator splits the string into one array element per character.

       sub(r, t, s)
              substitutes t for the first occurrence of the regular expression r in the string s.  If s  is  not
              given, $0 is used.

       gsub   same  as  sub  except  that  all  occurrences of the regular expression are replaced; sub and gsub
              return the number of replacements.

       sprintf(fmt, expr, ... )
              the string resulting from formatting expr ...  according to the printf(3) format fmt

       system(cmd)
              executes cmd and returns its exit status

       tolower(str)
              returns a copy of str with all upper-case characters translated to their corresponding  lower-case
              equivalents.

       toupper(str)
              returns  a copy of str with all lower-case characters translated to their corresponding upper-case
              equivalents.

       The ``function'' getline sets $0 to the next input record from the current input file; getline <file sets
       $0  to  the  next record from file.  getline x sets variable x instead.  Finally, cmd | getline pipes the
       output of cmd into getline; each call of getline returns the next line of output from cmd.  In all cases,
       getline returns 1 for a successful input, 0 for end of file, and -1 for an error.

       Patterns  are  arbitrary  Boolean  combinations  (with  !  ||  &&)  of regular expressions and relational
       expressions.  Regular expressions are as in egrep;  see  grep(1).   Isolated  regular  expressions  in  a
       pattern  apply  to  the entire line.  Regular expressions may also occur in relational expressions, using
       the operators ~ and !~.  /re/ is a constant regular expression; any string (constant or variable) may  be
       used as a regular expression, except in the position of an isolated regular expression in a pattern.

       A pattern may consist of two patterns separated by a comma; in this case, the action is performed for all
       lines from an occurrence of the first pattern though an occurrence of the second.

       A relational expression is one of the following:

              expression matchop regular-expression
              expression relop expression
              expression in array-name
              (expr,expr,...) in array-name

       where a relop is any of the six relational operators in C, and a matchop is  either  ~  (matches)  or  !~
       (does  not  match).   A  conditional  is  an arithmetic expression, a relational expression, or a Boolean
       combination of these.

       The special patterns BEGIN and END may be used to capture control before the first input line is read and
       after the last.  BEGIN and END do not combine with other patterns.

       Variable names with special meanings:

       CONVFMT
              conversion format used when converting numbers (default %.6g)

       FS     regular expression used to separate fields; also settable by option -Ffs.

       NF     number of fields in the current record

       NR     ordinal number of the current record

       FNR    ordinal number of the current record in the current file

       FILENAME
              the name of the current input file

       RS     input record separator (default newline)

       OFS    output field separator (default blank)

       ORS    output record separator (default newline)

       OFMT   output format for numbers (default %.6g)

       SUBSEP separates multiple subscripts (default 034)

       ARGC   argument count, assignable

       ARGV   argument array, assignable; non-null members are taken as filenames

       ENVIRON
              array of environment variables; subscripts are names.

       Functions may be defined (at the position of a pattern-action statement) thus:

              function foo(a, b, c) { ...; return x }

       Parameters  are  passed  by  value  if  scalar  and  by  reference if array name; functions may be called
       recursively.  Parameters are local to the function; all other variables are global.  Thus local variables
       may be created by providing excess parameters in the function definition.

EXAMPLES

       length($0) > 72
              Print lines longer than 72 characters.

       { print $2, $1 }
              Print first two fields in opposite order.

       BEGIN { FS = ",[ \t]*|[ \t]+" }
             { print $2, $1 }
              Same, with input fields separated by comma and/or blanks and tabs.

            { s += $1 }
       END  { print "sum is", s, " average is", s/NR }
              Add up first column, print sum and average.

       /start/, /stop/
              Print all lines between start/stop pairs.

       BEGIN     {    # Simulate echo(1)
            for (i = 1; i < ARGC; i++) printf "%s ", ARGV[i]
            printf "\n"
            exit }

SEE ALSO

       lex(1), sed(1)
       A.  V.  Aho, B. W. Kernighan, P. J. Weinberger, The AWK Programming Language, Addison-Wesley, 1988.  ISBN
       0-201-07981-X

BUGS

       There are no explicit conversions between numbers and strings.  To force an expression to be treated as a
       number add 0 to it; to force it to be treated as a string concatenate "" to it.
       The scope rules for variables in functions are a botch; the syntax is worse.

                                                                                                 ORIGINAL-AWK(1)