201 lines
4.0 KiB
Plaintext
201 lines
4.0 KiB
Plaintext
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.ds PX \s-1POSIX\s+1
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.ds UX \s-1UNIX\s+1
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.ds AN \s-1ANSI\s+1
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.TH GAWK 1 "May 28 1991" "Free Software Foundation" "Utility Commands"
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.SH NAME
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gawk \- pattern scanning and processing language
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.SH SYNOPSIS
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.B gawk
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[
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.B \-W
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.I gawk-options
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] [
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.BI \-F\^ fs
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] [
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.B \-v
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.IR var = val
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]
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.B \-f
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.I program-file
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[
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.B \-\^\-
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] file .\^.\^.
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.br
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.B gawk
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[
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.B \-W
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.I gawk-options
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] [
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.BI \-F\^ fs
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] [
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.B \-v
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.IR var = val
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] [
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.B \-\^\-
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]
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.I program-text
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file .\^.\^.
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.SH DESCRIPTION
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.I Gawk
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is the GNU Project's implementation of the AWK programming language.
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It conforms to the definition of the language in
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the \*(PX 1003.2 Command Language And Utilities Standard
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(draft 11).
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This version in turn is based on the description in
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.IR "The AWK Programming Language" ,
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by Aho, Kernighan, and Weinberger,
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with the additional features defined in the System V Release 4 version
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of \*(UX
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.IR awk .
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.I Gawk
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also provides some GNU-specific extensions.
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.PP
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The command line consists of options to
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.I gawk
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itself, the AWK program text (if not supplied via the
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.B \-f
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option), and values to be made
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available in the
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.B ARGC
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and
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.B ARGV
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pre-defined AWK variables.
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.SH OPTIONS
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.PP
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.I Gawk
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accepts the following options, which should be available on any implementation
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of the AWK language.
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.TP
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.BI \-F fs
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Use
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.I fs
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for the input field separator (the value of the
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.B FS
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predefined
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variable).
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.TP
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\fB\-v\fI var\fR\^=\^\fIval\fR
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Assign the value
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.IR val ,
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to the variable
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.IR var ,
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before execution of the program begins.
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Such variable values are available to the
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.B BEGIN
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block of an AWK program.
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.TP
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.BI \-f " program-file"
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Read the AWK program source from the file
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.IR program-file ,
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instead of from the first command line argument.
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Multiple
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.B \-f
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options may be used.
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.TP
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.B \-\^\-
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Signal the end of options. This is useful to allow further arguments to the
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AWK program itself to start with a ``\-''.
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This is mainly for consistency with the argument parsing convention used
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by most other \*(PX programs.
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.PP
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Following the \*(PX standard,
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.IR gawk -specific
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options are supplied via arguments to the
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.B \-W
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option. Multiple
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.B \-W
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options may be supplied, or multiple arguments may be supplied together
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if they are separated by commas, or enclosed in quotes and separated
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by white space.
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Case is ignored in arguments to the
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.B \-W
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option.
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.PP
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The
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.B \-W
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option accepts the following arguments:
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.TP \w'\fBcopyright\fR'u+1n
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.B compat
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Run in
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.I compatibility
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mode. In compatibility mode,
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.I gawk
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behaves identically to \*(UX
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.IR awk ;
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none of the GNU-specific extensions are recognized.
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.TP
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.PD 0
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.B copyleft
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.TP
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.PD
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.B copyright
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Print the short version of the GNU copyright information message on
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the error output.
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.TP
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.B lint
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Provide warnings about constructs that are
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dubious or non-portable to other AWK implementations.
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.TP
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.B posix
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This turns on
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.I compatibility
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mode, with the following additional restrictions:
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.RS
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.TP \w'\(bu'u+1n
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\(bu
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.B \ex
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escape sequences are not recognized.
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.TP
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\(bu
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The synonym
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.B func
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for the keyword
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.B function
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is not recognized.
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.TP
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\(bu
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The operators
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.B **
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and
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.B **=
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cannot be used in place of
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.B ^
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and
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.BR ^= .
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.RE
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.TP
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.B version
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Print version information for this particular copy of
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.I gawk
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on the error output.
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This is useful mainly for knowing if the current copy of
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.I gawk
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on your system
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is up to date with respect to whatever the Free Software Foundation
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is distributing.
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.PP
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Any other options are flagged as illegal, but are otherwise ignored.
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.SH AWK PROGRAM EXECUTION
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.PP
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An AWK program consists of a sequence of pattern-action statements
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and optional function definitions.
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.RS
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.PP
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\fIpattern\fB { \fIaction statements\fB }\fR
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.br
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\fBfunction \fIname\fB(\fIparameter list\fB) { \fIstatements\fB }\fR
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.RE
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.PP
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|
|
.I Gawk
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first reads the program source from the
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.IR program-file (s)
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if specified, or from the first non-option argument on the command line.
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The
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.B \-f
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option may be used multiple times on the command line.
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.I Gawk
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will read the program text as if all the
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.IR program-file s
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had been concatenated together. This is useful for building libraries
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of AWK functions, without having to include them in each new AWK
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