1551 lines
46 KiB
Plaintext
1551 lines
46 KiB
Plaintext
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.\" AWK Reference Card --- Arnold Robbins, arnold@gnu.org
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.\"
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.\" Copyright (C) 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
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.\"
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.\" Permission is granted to make and distribute verbatim copies of
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.\" this reference card provided the copyright notice and this permission
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.\" notice are preserved on all copies.
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.\"
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.\" Permission is granted to process this file through troff and print the
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.\" results, provided the printed document carries copying permission
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.\" notice identical to this one except for the removal of this paragraph
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.\" (this paragraph not being relevant to the printed reference card).
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" reference card under the conditions for verbatim copying, provided that
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.\" the entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Permission is granted to copy and distribute translations of this
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.\" reference card into another language, under the above conditions for
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.\" modified versions, except that this permission notice may be stated in
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.\" a translation approved by the Foundation.
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.\"
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.\" Strings to save typing
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.ds AK \*(FCawk\*(FR
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.ds GK \*(FCgawk\*(FR
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.ds NK Bell Labs \*(FCawk\*(FR
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.ds MK \*(FCmawk\*(FR
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.\"
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.\"
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.de TD\" tab defaults
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.ta .2i .78i 1i 1.2i 1.4i 1.7i
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..
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.de TE
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.TD
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..
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.sp
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.ce
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\*(CD\f(HB\s+8AWK REFERENCE\s0\*(FR
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.sp
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.\" --- Table Of Contents
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.ta 2.4i 2.6iR
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.lc .
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.ES
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.in +.2i
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.nf
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\*(FRAWK Program Execution 4
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Action Statements 7
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Arrays 9
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Bug Reports 15
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Command Line Arguments (standard) 2
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Command Line Arguments (\*(GK) 3
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Command Line Arguments (\*(MK) 4
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Conversions And Comparisons 10
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Copying Permissions 16
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Definitions 2
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Environment Variables 16
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Escape Sequences 7
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Expressions 9
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Fields 6
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FTP Information 16
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Historical Features (\*(GK) 16
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Input Control 11
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Lines And Statements 5
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.ig
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Localization 10
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..
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Numeric Functions 13
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Output Control 11
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Pattern Elements 7
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POSIX Character Classes (\*(GK) 6
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Printf Formats 12
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Records 6
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Regular Expressions 5
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Special Filenames 13
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String Functions 14
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Time Functions (\*(GK) 15
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User-defined Functions 15
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Variables 8\*(CX
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.in -.2i
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.EB "\s+2\f(HBCONTENTS\*(FR\s0"
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.sp
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.TD
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.fi
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\*(CD\*(FRThis reference card was written by Arnold Robbins.
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Brian Kernighan and Michael Brennan reviewed it; we thank them
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for their help.
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.sp
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.SL
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.sp
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.so SRCDIR/ad.block
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.\" a subtlety here; this line changes color. We rely on it
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.\" also to provide a blank line.
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\*(CD
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.SL
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.nf
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\*(FR\(co Copyright 1996-2000, Free Software Foundation
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59 Temple Place \(em Suite 330
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Boston, MA 02111-1307 USA
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.nf
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.BT
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.\"
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.\"
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.\" --- Definitions
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.fi
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.ES
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\*(CDThis card describes POSIX AWK, as well as the three
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freely available \*(AK implementations
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(see \fHFTP Information\fP below).
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\*(CLCommon extensions (in two or more versions) are printed in light blue.
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\*(CBFeatures specific to just one version\(emusually GNU AWK (\*(GK)\(emare
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printed in dark blue.
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\*(CRExceptions and deprecated features are printed in red.
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\*(CDFeatures mandated by POSIX are printed in black.
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.sp .5
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Several type faces are used to clarify the meaning:
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.br
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.nr IN \w'\(bu '
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\(bu \*(FC\*(CN\fP is used for computer input.
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.br
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.fi
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.in +\n(INu
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.ti -\n(INu
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\(bu\|\^\*(FI\*(IN\fP is used to indicate user input and for syntactic
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placeholders, such as \*(FIvariable\fP or \*(FIaction\fP.
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.in -\n(INu
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.br
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\(bu \*(RN is used for explanatory text.
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.sp .5
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\*(FInumber\fP \- a floating point number as in ANSI C, such as
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\*(FC3\*(FR,
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\*(FC2.3\*(FR,
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\*(FC.4\*(FR,
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\*(FC1.4e2\*(FR
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or
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\*(FC4.1E5\*(FR.
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.sp .5
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\*(FIescape sequences\fP \- a special sequence of characters beginning
|
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with a backslash, used to describe otherwise unprintable characters.
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(See \fHEscape Sequences\fP below.)
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.sp .5
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\*(FIstring\fP \- a group of characters enclosed in double quotes.
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Strings may contain \*(FIescape sequences\*(FR.
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.sp .5
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\*(FIregexp\fP \- a regular expression, either a regexp constant
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enclosed in forward slashes, or a dynamic regexp computed at run-time.
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Regexp constants may contain \*(FIescape sequences\*(FR.
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.sp .5
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\*(FIname\fP \- a variable, array or function name.
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.sp .5
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\*(FIentry\fP(\*(FIN\fP) \- entry \*(FIentry\fP in section \*(FIN\fP of the
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UNIX reference manual.
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.sp .5
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\*(FIpattern\fP \- an expression describing an input record to be matched.
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.sp .5
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\*(FIaction\fP \- statements to execute when an input record is matched.
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.sp .5
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\*(FIrule\fP \- a pattern-action pair, where the pattern or action may
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be missing.\*(CX
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.EB \s+2\f(HBDEFINITIONS\*(FR\s0
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.\" --- Command Line Arguments
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.ES
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.fi
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\*(CDCommand line arguments control setting the field separator,
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setting variables before the \*(FCBEGIN\fP rule is run, and
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the location of AWK program source code.
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Implementation-specific command line arguments change
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the behavior of the running interpreter.
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.sp .5
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.TS
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expand;
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l lw(2.2i).
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\*(FC\-F \*(FIfs\*(FR use \*(FIfs\fP for the input field separator.
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\*(FC\-v\*(FI var\*(FC\^=\^\*(FIval\*(FR T{
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assign the value \*(FIval\*(FR, to the variable \*(FIvar\*(FR,
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before execution of the program begins. Such
|
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variable values are available to the \*(FCBEGIN\fP rule.
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T}
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\*(FC\-f \*(FIprog-file\*(FR T{
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read the AWK program source from the file
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\*(FIprog-file\*(FR, instead of from the first command
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line argument. Multiple \*(FC\-f\*(FR options may be used.
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T}
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\*(FC\-\^\-\*(FR signal the end of options.
|
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.TE
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.sp .5
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.fi
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|||
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\*(CLThe following options are accepted by both \*(NK and \*(GK
|
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\*(CR(ignored by \*(GK, not in \*(MK).\*(CL
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.sp .5
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.nf
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.TS
|
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expand, tab(%);
|
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l lw(2.2i).
|
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\*(FC\-mf \*(FIval\*(FR%set the maximum number of fields to \*(FIval\fP
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\*(FC\-mr \*(FIval\*(FR%set the maximum record size to \*(FIval\fP\*(CX
|
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.TE
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.EB "\s+2\f(HBCOMMAND LINE ARGUMENTS (standard)\*(FR\s0"
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.BT
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.ES
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.fi
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\*(CDThe following options are specific to \*(GK. The \*(FC\-W\*(FR
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forms are for full POSIX compliance.
|
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|
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.sp .5
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.ig
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.\" This option is left undocumented, on purpose.
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\*(FC\-\^\-nostalgia\*(FR
|
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\*(FC\-W nostalgia\*(FR%T{
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|
|
provide a moment of nostalgia for
|
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long time \*(AK users.
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T}
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..
|
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.TS
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expand, tab(%);
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ls
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l lw(1.8i).
|
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\*(FC\-\^\-field-separator \*(FIfs\*(FR
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%just like \*(FC\-F\fP
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\*(FC\-\^\-assign \*(FIvar\*(FC\^=\^\*(FIval\*(FR%just like \*(FC\-v\fP
|
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\*(FC\-\^\-file \*(FIprog-file%\*(FRjust like \*(FC\-f\fP
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\*(FC\-\^\-traditional\*(FR
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\*(FC\-\^\-compat\*(FR
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\*(FC\-W compat\*(FR
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\*(FC\-W traditional\*(FR%T{
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turn off \*(GK-specific extensions
|
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(\*(FC\-\^\-traditional\*(FR preferred).
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T}
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\*(FC\-\^\-copyleft\*(FR
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\*(FC\-\^\-copyright\*(FR
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\*(FC\-W copyleft\*(FR
|
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\*(FC\-W copyright\*(FR%T{
|
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|
|
print the short version of the GNU
|
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copyright information on \*(FCstdout\*(FR.
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T}
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\*(FC\-\^\-help\*(FR
|
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\*(FC\-\^\-usage\*(FR
|
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\*(FC\-W help\*(FR
|
|||
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\*(FC\-W usage\*(FR%T{
|
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|
print a short summary of the available
|
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options on \*(FCstdout\*(FR, then exit zero.
|
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T}
|
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\*(FC\-\^\-lint\*(FR
|
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\*(FC\-W lint\*(FR%T{
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warn about constructs that are dubious
|
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or non-portable to other \*(AKs.
|
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T}
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\*(FC\-\^\-lint\-old\*(FR
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\*(FC\-W lint\-old\*(FR%T{
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warn about constructs that are not
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portable to the original version of
|
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Unix \*(AK.
|
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T}
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\*(FC\-\^\-posix\*(FR
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\*(FC\-W posix\*(FR%T{
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disable common and GNU extensions.
|
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Enable \*(FIinterval expressions\*(FR in regular
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expression matching (see \fHRegular
|
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Expressions\fP below).
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T}
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\*(FC\-\^\-re\-interval\*(FR
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\*(FC\-W re\-interval\*(FR%T{
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enable \*(FIinterval expressions\*(FR in regular
|
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expression matching (see \fHRegular
|
|||
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Expressions\fP below). Useful if
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\*(FC\-\^\-posix\*(FR is not specified.
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T}
|
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\*(FC\-\^\-source '\*(FItext\*(FC'\*(FR
|
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\*(FC\-W source '\*(FItext\*(FC'\*(FR%use \*(FItext\*(FR as AWK program source code.
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\*(FC\-\^\-version\*(FR
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\*(FC\-W version\*(FR%T{
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print version information on \*(FCstdout\fP
|
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and exit zero.
|
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T}
|
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.TE
|
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.sp .5
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.fi
|
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In compatibility mode,
|
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any other options are flagged as illegal, but are otherwise ignored.
|
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|
In normal operation, as long as program text has been supplied, unknown
|
|||
|
|
options are passed on to the AWK program in
|
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\*(FCARGV\*(FR
|
|||
|
|
for processing. This is most useful for running AWK
|
|||
|
|
programs via the \*(FC#!\*(FR executable interpreter mechanism.\*(CB
|
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|
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.EB "\s+2\f(HBCOMMAND LINE ARGUMENTS (\*(GK\f(HB)\*(FR\s0"
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.BT
|
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.ES
|
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.fi
|
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\*(CDThe following options are specific to \*(MK.
|
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|
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.sp .5
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.fi
|
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.TS
|
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|
expand;
|
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|
l lw(1.8i).
|
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|
|
\*(FC\-W dump\*(FR T{
|
|||
|
|
print an assembly listing of the program to
|
|||
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\*(FCstdout\fP and exit zero.
|
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T}
|
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|
|
\*(FC\-W exec \*(FIfile\*(FR T{
|
|||
|
|
read program text from \*(FIfile\fP. No other
|
|||
|
|
options are processed. Useful with \*(FC#!\fP.
|
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T}
|
|||
|
|
\*(FC\-W interactive\*(FR T{
|
|||
|
|
unbuffer \*(FCstdout\fP and line buffer \*(FCstdin\fP.
|
|||
|
|
Lines are always records, ignoring \*(FCRS\fP
|
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T}
|
|||
|
|
\*(FC\-W posix_space\*(FR T{
|
|||
|
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\*(FC\en\*(FR separates fields when \*(FCRS = "\^"\fP.
|
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T}
|
|||
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\*(FC\-W sprintf=\*(FInum\*(FR T{
|
|||
|
|
adjust the size of \*(MK's internal
|
|||
|
|
\*(FCsprintf\*(FR buffer.
|
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T}
|
|||
|
|
\*(FC\-W version\*(FR T{
|
|||
|
|
print version and copyright on
|
|||
|
|
\*(FCstdout\fP and limit information on \*(FCstderr\fP
|
|||
|
|
and exit zero.
|
|||
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T}
|
|||
|
|
.TE
|
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|
|
.sp .5
|
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.fi
|
|||
|
|
The options may be abbreviated using just the first letter, e.g.,
|
|||
|
|
\*(FC\-We\*(FR,
|
|||
|
|
\*(FC\-Wv\*(FR
|
|||
|
|
and so on.\*(CB
|
|||
|
|
.EB "\s+2\f(HBCOMMAND LINE ARGUMENTS (\*(MK\f(HB)\*(FR\s0"
|
|||
|
|
|
|||
|
|
.\" --- Awk Program Execution
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDAWK programs are a sequence of pattern-action statements
|
|||
|
|
and optional function definitions.
|
|||
|
|
.sp .5
|
|||
|
|
\*(FIpattern\*(FC { \*(FIaction statements\*(FC }\*(FR
|
|||
|
|
.br
|
|||
|
|
\*(FCfunction \*(FIname\*(FC(\*(FIparameter list\*(FC) { \*(FIstatements\*(FC }\*(FR
|
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|
|
.sp .5
|
|||
|
|
\*(AK first reads the program source from the
|
|||
|
|
\*(FIprog-file\*(FR(s), if specified,
|
|||
|
|
\*(CBfrom arguments to \*(FC\-\^\-source\*(FR,\*(CD
|
|||
|
|
or from the first non-option argument on the command line.
|
|||
|
|
The program text is read as if all the \*(FIprog-file\*(FR(s)
|
|||
|
|
\*(CBand command line
|
|||
|
|
source texts\*(CD had been concatenated.
|
|||
|
|
.sp .5
|
|||
|
|
AWK programs execute in the following order.
|
|||
|
|
First, all variable assignments specified via the \*(FC\-v\fP
|
|||
|
|
option are performed.
|
|||
|
|
Next, \*(AK executes the code in the
|
|||
|
|
\*(FCBEGIN\fP rules(s), if any, and then proceeds to read
|
|||
|
|
the files \*(FC1\fP through \*(FCARGC \- 1\fP in the \*(FCARGV\fP array.
|
|||
|
|
(Adjusting \*(FCARGC\fP and \*(FCARGV\fP thus provides control over
|
|||
|
|
the input files that will be processed.)
|
|||
|
|
If there are no files named on the command line,
|
|||
|
|
\*(AK reads the standard input.
|
|||
|
|
.sp .5
|
|||
|
|
If a command line argument has the form
|
|||
|
|
\*(FIvar\*(FC=\*(FIval\*(FR,
|
|||
|
|
it is treated as a variable assignment. The variable
|
|||
|
|
\*(FIvar\fP will be assigned the value \*(FIval\*(FR.
|
|||
|
|
(This happens after any \*(FCBEGIN\fP rule(s) have been run.)
|
|||
|
|
... delete this paragraph if no space
|
|||
|
|
Command line variable assignment
|
|||
|
|
is most useful for dynamically assigning values to the variables
|
|||
|
|
\*(AK uses to control how input is broken into fields and records. It
|
|||
|
|
is also useful for controlling state if multiple passes are needed over
|
|||
|
|
a single data file.
|
|||
|
|
.sp .5
|
|||
|
|
If the value of a particular element of \*(FCARGV\fP is empty
|
|||
|
|
(\*(FC"\^"\*(FR), \*(AK skips over it.
|
|||
|
|
.sp .5
|
|||
|
|
For each record in the input, \*(AK tests to see if it matches any
|
|||
|
|
\*(FIpattern\fP in the AWK program.
|
|||
|
|
For each pattern that the record matches, the associated
|
|||
|
|
\*(FIaction\fP is executed.
|
|||
|
|
The patterns are tested in the order they occur in the program.
|
|||
|
|
.sp .5
|
|||
|
|
Finally, after all the input is exhausted,
|
|||
|
|
\*(AK executes the code in the \*(FCEND\fP rule(s), if any.
|
|||
|
|
.sp .5
|
|||
|
|
If a program only has a \*(FCBEGIN\fP rule, no input files are processed.
|
|||
|
|
If a program only has an \*(FCEND\fP rule, the input will be read.
|
|||
|
|
\*(CX
|
|||
|
|
.EB "\s+2\f(HBAWK PROGRAM EXECUTION\*(FR\s0"
|
|||
|
|
|
|||
|
|
|
|||
|
|
.BT
|
|||
|
|
|
|||
|
|
.\" --- Lines And Statements
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDAWK is a line oriented language. The pattern comes first, and then the
|
|||
|
|
action. Action statements are enclosed in \*(FC{\fP and \*(FC}\*(FR.
|
|||
|
|
Either the pattern or the action may be missing, but
|
|||
|
|
not both. If the pattern is missing, the action will be
|
|||
|
|
executed for every input record.
|
|||
|
|
A missing action is equivalent to
|
|||
|
|
.sp .5
|
|||
|
|
\*(FC{ print }\fP
|
|||
|
|
.sp .5
|
|||
|
|
which prints the entire record.
|
|||
|
|
.sp .5
|
|||
|
|
Comments begin with the \*(FC#\*(FR character, and continue until the
|
|||
|
|
end of the line.
|
|||
|
|
Normally, a statement ends with a newline, but lines ending in
|
|||
|
|
a ``,'',
|
|||
|
|
\*(FC{\*(FR,
|
|||
|
|
\*(CB\*(FC?\*(FR,
|
|||
|
|
\*(FC:\*(FR,\*(CD
|
|||
|
|
\*(FC&&\*(FR
|
|||
|
|
or
|
|||
|
|
\*(FC||\*(FR
|
|||
|
|
are automatically continued.
|
|||
|
|
Lines ending in \*(FCdo\fP or \*(FCelse\fP
|
|||
|
|
also have their statements automatically continued on the following line.
|
|||
|
|
In other cases, a line can be continued by ending it with a ``\e'',
|
|||
|
|
in which case the newline will be ignored. However, a ``\e'' after a
|
|||
|
|
\*(FC#\*(FR is not special.
|
|||
|
|
.sp .5
|
|||
|
|
Multiple statements may be put on one line by separating them with a ``;''.
|
|||
|
|
This applies to both the statements within the action part of a
|
|||
|
|
pattern-action pair (the usual case)
|
|||
|
|
and to the pattern-action statements themselves.\*(CX
|
|||
|
|
.EB "\s+2\f(HBLINES AND STATEMENTS\*(FR\s0"
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
.\" --- Regular Expressions
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDRegular expressions are the extended kind originally defined by
|
|||
|
|
\*(FCegrep\fP.
|
|||
|
|
\*(CBAdditional GNU regexp operators are supported by \*(GK.
|
|||
|
|
A \*(FIword-constituent\fP character is a letter, digit, or
|
|||
|
|
underscore (\*(FC_\fP).\*(CD
|
|||
|
|
.sp .5
|
|||
|
|
.TS
|
|||
|
|
center, tab(~);
|
|||
|
|
cp8 sp8
|
|||
|
|
cp8 sp8
|
|||
|
|
lp8|lp8.
|
|||
|
|
.\" .vs 10
|
|||
|
|
_
|
|||
|
|
Summary of Regular Expressions
|
|||
|
|
In Decreasing Precedence
|
|||
|
|
_
|
|||
|
|
\*(FC(\^\*(FIr\*(FC)\*(FR~regular expression (for grouping)
|
|||
|
|
\*(FIc\*(FR~if non-special char, matches itself
|
|||
|
|
\*(FC\e\*(FI\^c\*(FR~turn off special meaning of \*(FIc\fP
|
|||
|
|
\*(FC^\*(FR~beginning of string (note: \*(FInot\fP line)
|
|||
|
|
\*(FC$\*(FR~end of string (note: \*(FInot\fP line)
|
|||
|
|
\*(FC.\*(FR~any single character, including newline
|
|||
|
|
\*(FC[\*(FR...\*(FC]\*(FR~any one character in ... or range
|
|||
|
|
\*(FC[^\*(FR...\*(FC]\*(FR~any one character not in ... or range
|
|||
|
|
\*(CB\*(FC\ey\*(FR~word boundary
|
|||
|
|
\*(FC\eB\*(FR~middle of a word
|
|||
|
|
\*(FC\e<\*(FR~beginning of a word
|
|||
|
|
\*(FC\e>\*(FR~end of a word
|
|||
|
|
\*(FC\ew\*(FR~any word-constituent character
|
|||
|
|
\*(FC\eW\*(FR~any non-word-constituent character
|
|||
|
|
\*(FC\e`\*(FR~beginning of a buffer (string)
|
|||
|
|
\*(FC\e'\*(FR~end of a buffer (string)\*(CD
|
|||
|
|
\*(FIr\*(FC*\*(FR~zero or more occurrences of \*(FIr\*(FR
|
|||
|
|
\*(FIr\*(FC+\*(FR~one or more occurrences of \*(FIr\*(FR
|
|||
|
|
\*(FIr\*(FC?\*(FR~zero or one occurrences of \*(FIr\*(FR
|
|||
|
|
\*(FIr\*(FC{\*(FIn\*(FC,\*(FIm\*(FC}\*(FR~\*(FIn\fP to \*(FIm\fP occurrences of \*(FIr\*(FR \*(CR(POSIX: see note below)\*(CD
|
|||
|
|
\*(FIr1\*(FC|\|\*(FIr2\*(FR~\*(FIr1\*(FR or \*(FIr2\*(FR
|
|||
|
|
.TE
|
|||
|
|
.sp .5
|
|||
|
|
.fi
|
|||
|
|
\*(CRThe \*(FIr\*(FC{\*(FIn\*(FC,\*(FIm\*(FC}\*(FR notation is called an
|
|||
|
|
\*(FIinterval expression\fP. POSIX mandates it for AWK regexps, but
|
|||
|
|
most \*(AKs don't implement it. \*(CBUse \*(FC\-\^\-re\-interval\*(FR
|
|||
|
|
or \*(FC\-\^\-posix\*(FR to enable
|
|||
|
|
this feature in \*(GK.\*(CX
|
|||
|
|
.EB "\s+2\f(HBREGULAR EXPRESSIONS\*(FR\s0"
|
|||
|
|
|
|||
|
|
|
|||
|
|
.BT
|
|||
|
|
|
|||
|
|
.\" --- POSIX Character Classes (gawk)
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDIn regular expressions, within character ranges
|
|||
|
|
(\*(FC[\*(FR...\*(FC]\*(FR),
|
|||
|
|
the notation \*(FC[[:\*(FIclass\*(FC:]]\*(FR defines characters classes:
|
|||
|
|
.sp .5
|
|||
|
|
.TS
|
|||
|
|
center, tab(~);
|
|||
|
|
lp8 lp8 lp8 lp8.
|
|||
|
|
\*(FCalnum\*(FR~alphanumeric~\*(FClower\*(FR~lower-case
|
|||
|
|
\*(FCalpha\*(FR~alphabetic~\*(FCprint\*(FR~printable
|
|||
|
|
\*(FCblank\*(FR~space or tab~\*(FCpunct\*(FR~punctuation
|
|||
|
|
\*(FCcntrl\*(FR~control~\*(FCspace\*(FR~whitespace
|
|||
|
|
\*(FCdigit\*(FR~decimal~\*(FCupper\*(FR~upper-case
|
|||
|
|
\*(FCgraph\*(FR~non-spaces~\*(FCxdigit\*(FR~hexadecimal\*(CB
|
|||
|
|
.TE
|
|||
|
|
.fi
|
|||
|
|
.EB "\s+2\f(HBPOSIX CHARACTER CLASSES (\*(GK\f(HB)\*(FR\s0"
|
|||
|
|
|
|||
|
|
.\" --- Records
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDNormally, records are separated by newline characters.
|
|||
|
|
Assigning values to the built-in variable \*(FCRS\*(FR
|
|||
|
|
controls how records are separated.
|
|||
|
|
If \*(FCRS\fP is any single character, that character separates records.
|
|||
|
|
\*(CLOtherwise, \*(FCRS\fP is a regular expression.
|
|||
|
|
\*(CR(Not \*(NK.)\*(CL
|
|||
|
|
Text in the input that matches this
|
|||
|
|
regular expression will separate the record.
|
|||
|
|
\*(CB\*(GK sets \*(FCRT\*(FR to the value of the
|
|||
|
|
input text that matched the regular expression.
|
|||
|
|
The value of \*(FCIGNORECASE\fP
|
|||
|
|
will also affect how records are separated when
|
|||
|
|
\*(FCRS\fP is a regular expression.\*(CD
|
|||
|
|
If \*(FCRS\fP is set to the null string,
|
|||
|
|
then records are separated by one or more blank lines.
|
|||
|
|
When \*(FCRS\fP is set to the null string,
|
|||
|
|
the newline character always acts as
|
|||
|
|
a field separator, in addition to whatever value
|
|||
|
|
\*(FCFS\fP may have.
|
|||
|
|
\*(CB\*(MK does not apply exceptional rules to \*(FCFS\fP
|
|||
|
|
when \*(FCRS = "\^"\fP.\*(CX
|
|||
|
|
.EB \s+2\f(HBRECORDS\*(FR\s0
|
|||
|
|
|
|||
|
|
.\" --- Fields
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDAs each input record is read, \*(AK splits the record into
|
|||
|
|
\*(FIfields\*(FR, using the value of the \*(FCFS\fP
|
|||
|
|
variable as the field separator.
|
|||
|
|
If \*(FCFS\fP is a single character,
|
|||
|
|
fields are separated by that character.
|
|||
|
|
\*(CLIf \*(FCFS\fP is the null string,
|
|||
|
|
then each individual character becomes a separate field.\*(CD
|
|||
|
|
Otherwise, \*(FCFS\fP is expected to be a full regular expression.
|
|||
|
|
In the special case that \*(FCFS\fP
|
|||
|
|
is a single space, fields are separated
|
|||
|
|
by runs of spaces and/or tabs
|
|||
|
|
\*(CLand/or newlines\*(CD.
|
|||
|
|
Leading and trailing whitespace are ignored.
|
|||
|
|
\*(CBThe value of \*(FCIGNORECASE\fP
|
|||
|
|
will also affect how fields are split when
|
|||
|
|
\*(FCFS\fP is a regular expression.\*(CD
|
|||
|
|
.sp .5
|
|||
|
|
\*(CBIf the \*(FCFIELDWIDTHS\fP
|
|||
|
|
variable is set to a space separated list of numbers, each field is
|
|||
|
|
expected to have a fixed width, and \*(GK
|
|||
|
|
will split up the record using the specified widths.
|
|||
|
|
The value of \*(FCFS\fP is ignored.
|
|||
|
|
Assigning a new value to \*(FCFS\fP
|
|||
|
|
overrides the use of \*(FCFIELDWIDTHS\*(FR,
|
|||
|
|
and restores the default behavior.\*(CD
|
|||
|
|
.sp .5
|
|||
|
|
Each field in the input record may be referenced by its position,
|
|||
|
|
\*(FC$1\*(FR, \*(FC$2\*(FR and so on.
|
|||
|
|
\*(FC$0\fP is the whole record.
|
|||
|
|
Fields may also be assigned new values.
|
|||
|
|
.sp .5
|
|||
|
|
The variable \*(FCNF\fP
|
|||
|
|
is set to the total number of fields in the input record.
|
|||
|
|
.sp .5
|
|||
|
|
References to non-existent fields (i.e., fields after \*(FC$NF\*(FR)
|
|||
|
|
produce the null-string. However, assigning to a non-existent field
|
|||
|
|
(e.g., \*(FC$(NF+2) = 5\*(FR) will increase the value of
|
|||
|
|
\*(FCNF\*(FR, create any intervening fields with the null string as their value,
|
|||
|
|
and cause the value of \*(FC$0\fP
|
|||
|
|
to be recomputed with the fields being separated by the
|
|||
|
|
value of \*(FCOFS\*(FR.
|
|||
|
|
References to negative numbered fields cause a fatal error.
|
|||
|
|
Decreasing the value of \*(FCNF\fP causes the trailing fields to be lost
|
|||
|
|
\*(CR(not \*(NK).\*(CX
|
|||
|
|
.EB \s+2\f(HBFIELDS\*(FR\s0
|
|||
|
|
|
|||
|
|
.BT
|
|||
|
|
|
|||
|
|
.\" --- Pattern Elements
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDAWK patterns may be one of the following.
|
|||
|
|
.sp .5
|
|||
|
|
.nf
|
|||
|
|
\*(FCBEGIN
|
|||
|
|
END
|
|||
|
|
\*(FIexpression
|
|||
|
|
pat1\*(FC,\*(FIpat2\*(FR
|
|||
|
|
.sp .5
|
|||
|
|
.fi
|
|||
|
|
\*(FCBEGIN\fP and \*(FCEND\fP are special patterns that provide start-up
|
|||
|
|
and clean-up actions respectively. They must have actions. There can
|
|||
|
|
be multiple \*(FCBEGIN\fP and \*(FCEND\fP rules; they are merged and
|
|||
|
|
executed as if there had just been one large rule. They may occur anywhere
|
|||
|
|
in a program, including different source files.
|
|||
|
|
.sp .5
|
|||
|
|
Expression patterns can be any expression, as described
|
|||
|
|
under \fHExpressions\fP.
|
|||
|
|
.sp .5
|
|||
|
|
The \*(FIpat1\*(FC,\*(FIpat2\*(FR pattern
|
|||
|
|
is called a \*(FIrange pattern\*(FR.
|
|||
|
|
It matches all input records starting with a record that matches
|
|||
|
|
\*(FIpat1\*(FR, and continuing until a record that matches
|
|||
|
|
\*(FIpat2\*(FR, inclusive.
|
|||
|
|
It does not combine with any other pattern expression.\*(CX
|
|||
|
|
.EB "\s+2\f(HBPATTERN ELEMENTS\*(FR\s0"
|
|||
|
|
|
|||
|
|
|
|||
|
|
.\" --- Action Statements
|
|||
|
|
.ES
|
|||
|
|
.nf
|
|||
|
|
\*(CD\*(FCif (\*(FIcondition\*(FC) \*(FIstatement\*(FR [ \*(FCelse\*(FI statement \*(FR]
|
|||
|
|
\*(FCwhile (\*(FIcondition\*(FC) \*(FIstatement \*(FR
|
|||
|
|
\*(FCdo \*(FIstatement \*(FCwhile (\*(FIcondition\*(FC)\*(FR
|
|||
|
|
\*(FCfor (\*(FIexpr1\*(FC; \*(FIexpr2\*(FC; \*(FIexpr3\*(FC) \*(FIstatement\*(FR
|
|||
|
|
\*(FCfor (\*(FIvar \*(FCin\*(FI array\*(FC) \*(FIstatement\*(FR
|
|||
|
|
.ig
|
|||
|
|
\*(CB\*(FCabort\*(FR [ \*(FIexpression\*(FR ]\*(CD
|
|||
|
|
..
|
|||
|
|
\*(FCbreak\*(FR
|
|||
|
|
\*(FCcontinue\*(FR
|
|||
|
|
\*(FCdelete \*(FIarray\^\*(FC[\^\*(FIindex\^\*(FC]\*(FR
|
|||
|
|
\*(CL\*(FCdelete \*(FIarray\^\*(FR\*(CD
|
|||
|
|
\*(FCexit\*(FR [ \*(FIexpression\*(FR ]
|
|||
|
|
\*(FCnext\*(FR
|
|||
|
|
\*(CL\*(FCnextfile\*(FR \*(CR(not \*(MK)\*(CD
|
|||
|
|
\*(FC{ \*(FIstatements \*(FC}\*(CX
|
|||
|
|
.EB "\s+2\f(HBACTION STATEMENTS\*(FR\s0"
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
.\" --- Escape Sequences
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDWithin strings constants (\*(FC"..."\fP) and regexp
|
|||
|
|
constants (\*(FC/.../\fP), escape sequences may be used to
|
|||
|
|
generate otherwise unprintable characters. This table lists
|
|||
|
|
the available escape sequences.
|
|||
|
|
.sp .5
|
|||
|
|
.ig
|
|||
|
|
\*(CB\*(FCPROCINFO\fP T{
|
|||
|
|
elements of this array provide access to info
|
|||
|
|
about the running AWK program. See
|
|||
|
|
\*(AM for details.\*(CD
|
|||
|
|
T}
|
|||
|
|
..
|
|||
|
|
.TS
|
|||
|
|
center, tab(~);
|
|||
|
|
lp8 lp8 lp8 lp8.
|
|||
|
|
\*(FC\ea\fP~alert (bell)~\*(FC\er\fP~carriage return
|
|||
|
|
\*(FC\eb\fP~backspace~\*(FC\et\fP~horizontal tab
|
|||
|
|
\*(FC\ef\fP~form feed~\*(FC\ev\fP~vertical tab
|
|||
|
|
\*(FC\en\fP~newline~\*(FC\e\e\fP~backslash
|
|||
|
|
\*(FC\e\*(FIddd\*(FR~octal value \*(FIddd\fP~\*(CL\*(FC\ex\*(FIhh\*(FR~hex value \*(FIhh\fP\*(CD
|
|||
|
|
\*(FC\e"\fP~double quote~\*(FC\e/\fP~forward slash\*(CX
|
|||
|
|
.TE
|
|||
|
|
.EB "\s+2\f(HBESCAPE SEQUENCES\*(FR\s0"
|
|||
|
|
|
|||
|
|
|
|||
|
|
.BT
|
|||
|
|
|
|||
|
|
.\" --- Variables
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
.TS
|
|||
|
|
expand;
|
|||
|
|
l lw(2i).
|
|||
|
|
\*(FCARGC\fP T{
|
|||
|
|
number of command line arguments.
|
|||
|
|
T}
|
|||
|
|
\*(CB\*(FCARGIND\fP T{
|
|||
|
|
index in \*(FCARGV\fP of current data file.\*(CD
|
|||
|
|
T}
|
|||
|
|
\*(FCARGV\fP T{
|
|||
|
|
array of command line arguments. Indexed from
|
|||
|
|
0 to \*(FCARGC\fP \- 1. Dynamically changing the
|
|||
|
|
contents of \*(FCARGV\fP can control the files used
|
|||
|
|
for data.
|
|||
|
|
T}
|
|||
|
|
\*(FCCONVFMT\fP T{
|
|||
|
|
conversion format for numbers, default value
|
|||
|
|
is \*(FC"%.6g"\*(FR.
|
|||
|
|
T}
|
|||
|
|
\*(FCENVIRON\fP T{
|
|||
|
|
array containing the the current environment.
|
|||
|
|
The array is indexed by the environment
|
|||
|
|
variables, each element being the value of
|
|||
|
|
that variable.
|
|||
|
|
T}
|
|||
|
|
\*(CB\*(FCERRNO\fP T{
|
|||
|
|
contains a string describing the error when a
|
|||
|
|
redirection or read for \*(FCgetline\*(FR fails, or if
|
|||
|
|
\*(FCclose()\*(FR fails.
|
|||
|
|
T}
|
|||
|
|
\*(FCFIELDWIDTHS\fP T{
|
|||
|
|
white-space separated list of fieldwidths. Used
|
|||
|
|
to parse the input into fields of fixed width,
|
|||
|
|
instead of the value of \*(FCFS\fP.\*(CD
|
|||
|
|
T}
|
|||
|
|
\*(FCFILENAME\fP T{
|
|||
|
|
name of the current input file. If no files given
|
|||
|
|
on the command line, \*(FCFILENAME\fP is ``\-''.
|
|||
|
|
\*(FCFILENAME\fP is undefined inside the \*(FCBEGIN\fP rule
|
|||
|
|
(unless set by \*(FCgetline\fP).
|
|||
|
|
T}
|
|||
|
|
\*(FCFNR\fP T{
|
|||
|
|
number of the input record in current input file.
|
|||
|
|
T}
|
|||
|
|
\*(FCFS\fP T{
|
|||
|
|
input field separator, a space by default
|
|||
|
|
(see \fHFields\fP above).
|
|||
|
|
T}
|
|||
|
|
\*(CB\*(FCIGNORECASE\fP T{
|
|||
|
|
if non-zero, all regular expression and string
|
|||
|
|
operations ignore case. \*(CRIn versions of \*(GK
|
|||
|
|
prior to 3.0, \*(FCIGNORECASE\fP only affected
|
|||
|
|
regular expression operations and \*(FCindex()\*(FR.\*(CD
|
|||
|
|
T}
|
|||
|
|
\*(FCNF\fP T{
|
|||
|
|
number of fields in the current input record.
|
|||
|
|
T}
|
|||
|
|
\*(FCNR\fP T{
|
|||
|
|
total number of input records seen so far.
|
|||
|
|
T}
|
|||
|
|
\*(FCOFMT\fP T{
|
|||
|
|
output format for numbers, \*(FC"%.6g"\*(FR, by default.
|
|||
|
|
\*(CROld versions of \*(AK also used this for number
|
|||
|
|
to string conversion instead of \*(FCCONVFMT\fP.\*(CD
|
|||
|
|
T}
|
|||
|
|
\*(FCOFS\fP T{
|
|||
|
|
output field separator, a space by default.
|
|||
|
|
T}
|
|||
|
|
\*(FCORS\fP T{
|
|||
|
|
output record separator, a newline by default.
|
|||
|
|
T}
|
|||
|
|
\*(FCRS\fP T{
|
|||
|
|
input record separator, a newline by default
|
|||
|
|
(see \fHRecords\fP above).
|
|||
|
|
T}
|
|||
|
|
\*(CB\*(FCRT\fP T{
|
|||
|
|
record terminator. \*(GK sets \*(FCRT\fP to the input
|
|||
|
|
text that matched the character or regular
|
|||
|
|
expression specified by \*(FCRS\*(FR.\*(CD
|
|||
|
|
T}
|
|||
|
|
\*(FCRSTART\fP T{
|
|||
|
|
index of the first character matched by
|
|||
|
|
\*(FCmatch()\*(FR; 0 if no match.
|
|||
|
|
T}
|
|||
|
|
\*(FCRLENGTH\fP T{
|
|||
|
|
length of the string matched by \*(FCmatch()\*(FR;
|
|||
|
|
\-1 if no match.
|
|||
|
|
T}
|
|||
|
|
\*(FCSUBSEP\fP T{
|
|||
|
|
character(s) used to separate multiple subscripts
|
|||
|
|
in array elements, by default \*(FC"\e034"\*(FR. (see
|
|||
|
|
\fHArrays\fP below).\*(CX
|
|||
|
|
T}
|
|||
|
|
.TE
|
|||
|
|
.EB \s+2\f(HBVARIABLES\*(FR\s0
|
|||
|
|
|
|||
|
|
.BT
|
|||
|
|
|
|||
|
|
.\" --- Arrays
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDAn arrays subscript is an expression between square brackets
|
|||
|
|
(\*(FC[ \*(FRand \*(FC]\*(FR).
|
|||
|
|
If the expression is a list
|
|||
|
|
\*(FC(\*(FIexpr\*(FC, \*(FIexpr \*(FC...)\*(FR,
|
|||
|
|
then the subscript is a string consisting of the
|
|||
|
|
concatenation of the (string) value of each expression,
|
|||
|
|
separated by the value of the \*(FCSUBSEP\fP variable.
|
|||
|
|
This simulates multi-dimensional
|
|||
|
|
arrays. For example:
|
|||
|
|
.nf
|
|||
|
|
.sp .5
|
|||
|
|
\*(FCi = "A";\^ j = "B";\^ k = "C"
|
|||
|
|
x[i, j, k] = "hello, world\en"\*(FR
|
|||
|
|
.sp .5
|
|||
|
|
.fi
|
|||
|
|
assigns \*(FC"hello, world\en"\*(FR to the element of the array
|
|||
|
|
\*(FCx\fP
|
|||
|
|
indexed by the string \*(FC"A\e034B\e034C"\*(FR. All arrays in AWK
|
|||
|
|
are associative, i.e., indexed by string values.
|
|||
|
|
.sp .5
|
|||
|
|
Use the special operator \*(FCin\fP in an \*(FCif\fP
|
|||
|
|
or \*(FCwhile\fP statement to see if a particular value is
|
|||
|
|
an array index.
|
|||
|
|
.sp .5
|
|||
|
|
.nf
|
|||
|
|
\*(FCif (val in array)
|
|||
|
|
print array[val]\*(FR
|
|||
|
|
.sp .5
|
|||
|
|
.fi
|
|||
|
|
If the array has multiple subscripts, use
|
|||
|
|
\*(FC(i, j) in array\*(FR.
|
|||
|
|
.sp .5
|
|||
|
|
Use the \*(FCin\fP construct in a \*(FCfor\fP
|
|||
|
|
loop to iterate over all the elements of an array.
|
|||
|
|
.sp .5
|
|||
|
|
Use the \*(FCdelete\fP statement to delete an
|
|||
|
|
element from an array.
|
|||
|
|
\*(CLSpecifying just the array name without a subscript in
|
|||
|
|
the \*(FCdelete\fP
|
|||
|
|
statement deletes the entire contents of an array.\*(CX
|
|||
|
|
.EB \s+2\f(HBARRAYS\*(FR\s0
|
|||
|
|
|
|||
|
|
.\" --- Expressions
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDExpressions are used as patterns, for controlling conditional action
|
|||
|
|
statements, and to produce parameter values when calling functions.
|
|||
|
|
Expressions may also be used as simple statements,
|
|||
|
|
particularly if they have side-effects such as assignment.
|
|||
|
|
Expressions mix \*(FIoperands\fP and \*(FIoperators\fP. Operands are
|
|||
|
|
constants, fields, variables, array elements, and the return
|
|||
|
|
values from function calls (both built-in and user-defined).
|
|||
|
|
.sp .5
|
|||
|
|
Regexp constants (\*(FC/\*(FIpat\*(FC/\*(FR), when used as simple expressions,
|
|||
|
|
i.e., not used on the right-hand side of
|
|||
|
|
\*(FC~\fP and \*(FC!~\fP, or as arguments to the
|
|||
|
|
\*(CB\*(FCgensub()\fP,\*(CD
|
|||
|
|
\*(FCgsub()\fP,
|
|||
|
|
\*(FCmatch()\fP,
|
|||
|
|
\*(FCsplit()\fP,
|
|||
|
|
and
|
|||
|
|
\*(FCsub()\fP,
|
|||
|
|
functions, mean \*(FC$0 ~ /\*(FIpat\*(FC/\*(FR.
|
|||
|
|
.sp .5
|
|||
|
|
The AWK operators, in order of decreasing precedence, are
|
|||
|
|
.sp .5
|
|||
|
|
.fi
|
|||
|
|
.TS
|
|||
|
|
expand;
|
|||
|
|
l lw(1.8i).
|
|||
|
|
\*(FC(\&...)\*(FR grouping
|
|||
|
|
\*(FC$\fP field reference
|
|||
|
|
\*(FC++ \-\^\-\fP T{
|
|||
|
|
increment and decrement,
|
|||
|
|
prefix and postfix
|
|||
|
|
T}
|
|||
|
|
\*(FC^\fP \*(CL\*(FC**\*(FR\*(CD exponentiation
|
|||
|
|
\*(FC+ \- !\fP unary plus, unary minus, and logical negation
|
|||
|
|
\*(FC* / %\fP multiplication, division, and modulus
|
|||
|
|
\*(FC+ \-\fP addition and subtraction
|
|||
|
|
\*(FIspace\fP string concatenation
|
|||
|
|
\*(FC< >\fP less than, greater than
|
|||
|
|
\*(FC<= >=\fP less than or equal, greater than or equal
|
|||
|
|
\*(FC!= ==\fP not equal, equal
|
|||
|
|
\*(FC~ !~\fP regular expression match, negated match
|
|||
|
|
\*(FCin\fP array membership
|
|||
|
|
\*(FC&&\fP logical AND, short circuit
|
|||
|
|
\*(FC||\fP logical OR, short circuit
|
|||
|
|
\*(FC?\^:\fP in-line conditional expression
|
|||
|
|
.T&
|
|||
|
|
l s
|
|||
|
|
l lw(1.8i).
|
|||
|
|
\*(FC=\0+=\0\-=\0*=\0/=\0%=\0^=\0\*(CL**=\*(CD\fP
|
|||
|
|
assignment operators\*(CX
|
|||
|
|
.TE
|
|||
|
|
.EB \s+2\f(HBEXPRESSIONS\*(FR\s0
|
|||
|
|
|
|||
|
|
|
|||
|
|
.BT
|
|||
|
|
|
|||
|
|
.\" --- Conversions and Comparisons
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDVariables and fields may be (floating point) numbers, strings or both.
|
|||
|
|
Context determines how the value of a variable is interpreted. If used in
|
|||
|
|
a numeric expression, it will be treated as a number, if used as a string
|
|||
|
|
it will be treated as a string.
|
|||
|
|
.sp .5
|
|||
|
|
To force a variable to be treated as a number, add 0 to it; to force it
|
|||
|
|
to be treated as a string, concatenate it with the null string.
|
|||
|
|
.sp .5
|
|||
|
|
When a string must be converted to a number, the conversion is accomplished
|
|||
|
|
using \*(FIatof\*(FR(3).
|
|||
|
|
A number is converted to a string by using the value of \*(FCCONVFMT\fP
|
|||
|
|
as a format string for \*(FIsprintf\*(FR(3),
|
|||
|
|
with the numeric value of the variable as the argument.
|
|||
|
|
However, even though all numbers in AWK are floating-point,
|
|||
|
|
integral values are \*(FIalways\fP converted as integers.
|
|||
|
|
.sp .5
|
|||
|
|
Comparisons are performed as follows:
|
|||
|
|
If two variables are numeric, they are compared numerically.
|
|||
|
|
If one value is numeric and the other has a string value that is a
|
|||
|
|
``numeric string,'' then comparisons are also done numerically.
|
|||
|
|
Otherwise, the numeric value is converted to a string, and a string
|
|||
|
|
comparison is performed.
|
|||
|
|
Two strings are compared, of course, as strings.
|
|||
|
|
\*(CRAccording to the POSIX standard, even if two strings are
|
|||
|
|
numeric strings, a numeric comparison is performed. However, this is
|
|||
|
|
clearly incorrect, and none of the three free \*(AK\*(FRs do this.\*(CD
|
|||
|
|
.sp .5
|
|||
|
|
Note that string constants, such as \*(FC"57"\fP, are \*(FInot\fP
|
|||
|
|
numeric strings, they are string constants. The idea of ``numeric string''
|
|||
|
|
only applies to fields, \*(FCgetline\fP input,
|
|||
|
|
\*(FCFILENAME\*(FR, \*(FCARGV\fP elements, \*(FCENVIRON\fP
|
|||
|
|
elements and the elements of an array created by
|
|||
|
|
\*(FCsplit()\fP that are numeric strings.
|
|||
|
|
The basic idea is that \*(FIuser input\*(FR,
|
|||
|
|
and only user input, that looks numeric,
|
|||
|
|
should be treated that way.
|
|||
|
|
.sp .5
|
|||
|
|
Uninitialized variables have the numeric value 0 and the string value
|
|||
|
|
\*(FC"\^"\fP
|
|||
|
|
(the null, or empty, string).\*(CX
|
|||
|
|
.EB "\s+2\f(HBCONVERSIONS AND COMPARISONS\*(FR\s0"
|
|||
|
|
|
|||
|
|
.ig
|
|||
|
|
.\" --- Localization
|
|||
|
|
.ES
|
|||
|
|
.nf
|
|||
|
|
.ce 100
|
|||
|
|
\*(CDThis
|
|||
|
|
section
|
|||
|
|
is
|
|||
|
|
under
|
|||
|
|
construction.
|
|||
|
|
.sp .5
|
|||
|
|
This
|
|||
|
|
section
|
|||
|
|
is
|
|||
|
|
under
|
|||
|
|
construction.\*(CB
|
|||
|
|
.ce 0
|
|||
|
|
.EB "\s+2\f(HBLOCALIZATION\*(FR\s0"
|
|||
|
|
..
|
|||
|
|
|
|||
|
|
.ig
|
|||
|
|
.ps +2
|
|||
|
|
.ce 1
|
|||
|
|
\*(CD\fHISBN: 0-916151-97-2\*(FR
|
|||
|
|
.ps -2
|
|||
|
|
..
|
|||
|
|
|
|||
|
|
.BT
|
|||
|
|
|
|||
|
|
|
|||
|
|
.\" --- Input Control
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
.TS
|
|||
|
|
expand;
|
|||
|
|
l lw(1.8i).
|
|||
|
|
\*(CD\*(FCclose(\*(FIfile\*(FC)\*(FR close input file or pipe.
|
|||
|
|
\*(FCgetline\fP T{
|
|||
|
|
set \*(FC$0\fP from next input record;
|
|||
|
|
set \*(FCNF\*(FR, \*(FCNR\*(FR, \*(FCFNR\*(FR.
|
|||
|
|
T}
|
|||
|
|
\*(FCgetline < \*(FIfile\*(FR set \*(FC$0\fP from next record of \*(FIfile\*(FR; set \*(FCNF\*(FR.
|
|||
|
|
\*(FCgetline \*(FIv\*(FR T{
|
|||
|
|
set \*(FIv\fP from next input record;
|
|||
|
|
set \*(FCNR\*(FR, \*(FCFNR\*(FR.
|
|||
|
|
T}
|
|||
|
|
\*(FCgetline \*(FIv \*(FC< \*(FIfile\*(FR set \*(FIv\fP from next record of \*(FIfile\*(FR.
|
|||
|
|
\*(FIcmd \*(FC| getline\*(FR pipe into \*(FCgetline\*(FR; set \*(FC$0\*(FR, \*(FCNF\*(FR.
|
|||
|
|
\*(FIcmd \*(FC| getline \*(FIv\*(FR pipe into \*(FCgetline\*(FR; set \*(FIv\*(FR.
|
|||
|
|
.TE
|
|||
|
|
.fi
|
|||
|
|
.in +.2i
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCnext\fP
|
|||
|
|
.br
|
|||
|
|
stop processing the current input
|
|||
|
|
record. Read next input record and
|
|||
|
|
start over with the first pattern in the
|
|||
|
|
program. Upon end of the input data,
|
|||
|
|
execute any \*(FCEND\fP rule(s).
|
|||
|
|
.br
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(CL\*(FCnextfile\fP
|
|||
|
|
.br
|
|||
|
|
stop processing the current input file.
|
|||
|
|
The next input record comes from the
|
|||
|
|
next input file. \*(FCFILENAME\fP \*(CBand
|
|||
|
|
\*(FCARGIND\fP\*(CL are updated, \*(FCFNR\fP is reset to 1,
|
|||
|
|
and processing starts over with the first
|
|||
|
|
pattern in the AWK program. Upon end
|
|||
|
|
of input data, execute any \*(FCEND\fP rule(s).
|
|||
|
|
\*(CREarlier versions of \*(GK used
|
|||
|
|
\*(FCnext file\*(FR, as two words. This
|
|||
|
|
generates a warning message and will
|
|||
|
|
eventually be removed. \*(CR\*(MK does not
|
|||
|
|
currently support \*(FCnextfile\*(FR.\*(CD
|
|||
|
|
.in -.2i
|
|||
|
|
.sp .5
|
|||
|
|
.fi
|
|||
|
|
\*(FCgetline\*(FR returns 0 on end of file, and \-1 on an
|
|||
|
|
error.\*(CX
|
|||
|
|
.EB "\s+2\f(HBINPUT CONTROL\*(FR\s0"
|
|||
|
|
|
|||
|
|
.\" --- Output Control
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
.in +.2i
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(CD\*(FCclose(\*(FIfile\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
close output file or pipe.
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(CL\*(FCfflush(\*(FR[\*(FIfile\^\*(FR]\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
flush any buffers associated
|
|||
|
|
with the open output file or pipe \*(FIfile\*(FR.\*(CD
|
|||
|
|
\*(CBIf \*(FIfile\fP is missing, then standard output is flushed.
|
|||
|
|
If \*(FIfile\fP is the null string, then all open output files and pipes
|
|||
|
|
are flushed \*(CR(not \*(NK)\*(CD.
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCprint\fP
|
|||
|
|
.br
|
|||
|
|
print the current record. The output record is terminated
|
|||
|
|
with the value of \*(FCORS\fP.
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCprint \*(FIexpr-list\*(FR
|
|||
|
|
.br
|
|||
|
|
print expressions. Each expression is separated
|
|||
|
|
by the value of \*(FCOFS\fP. The output record is
|
|||
|
|
terminated with the value of \*(FCORS\fP.
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCprintf \*(FIfmt\*(FC, \*(FIexpr-list\*(FR
|
|||
|
|
.br
|
|||
|
|
format and print (see \fHPrintf Formats\fP below).
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCsystem(\*(FIcmd\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
execute the command \*(FIcmd\*(FR,
|
|||
|
|
and return the exit status
|
|||
|
|
\*(CR(may not be available on non-POSIX systems)\*(CD.
|
|||
|
|
.sp .5
|
|||
|
|
.in -.2i
|
|||
|
|
I/O redirections may be used with both \*(FCprint\fP and \*(FCprintf\fP.
|
|||
|
|
.sp .5
|
|||
|
|
.in +.2i
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(CD\*(FCprint "hello" > \*(FIfile\*(FR
|
|||
|
|
.br
|
|||
|
|
Print data to \*(FIfile\fP. The first time the file is written to, it
|
|||
|
|
will be truncated. Subsequent commands append data.
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCprint "hello" >> \*(FIfile\*(FR
|
|||
|
|
.br
|
|||
|
|
Append data to \*(FIfile\fP. The previous contents of the file are not lost.
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCprint "hello" | \*(FIcmd\*(FR
|
|||
|
|
.br
|
|||
|
|
Print data down a pipeline to \*(FIcmd\*(FR.\*(CX
|
|||
|
|
.in -.2i
|
|||
|
|
.EB "\s+2\f(HBOUTPUT CONTROL\*(FR\s0"
|
|||
|
|
|
|||
|
|
.BT
|
|||
|
|
|
|||
|
|
|
|||
|
|
.\" --- Printf Formats
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDThe \*(FCprintf\fP statement and
|
|||
|
|
\*(FCsprintf()\fP function
|
|||
|
|
accept the following conversion specification formats:
|
|||
|
|
.sp .5
|
|||
|
|
.nf
|
|||
|
|
\*(FC%c\fP an \s-1ASCII\s+1 character
|
|||
|
|
\*(FC%d\fP a decimal number (the integer part)
|
|||
|
|
\*(FC%i\fP a decimal number (the integer part)
|
|||
|
|
\*(FC%e\fP a floating point number of the form
|
|||
|
|
\*(FC[\-]d.dddddde[+\^\-]dd\*(FR
|
|||
|
|
\*(FC%E\fP like \*(FC%e\fP, but use \*(FCE\fP instead of \*(FCe\*(FR
|
|||
|
|
\*(FC%f\fP a floating point number of the form
|
|||
|
|
\*(FC[\-]ddd.dddddd\*(FR
|
|||
|
|
\*(FC%g\fP use \*(FC%e\fP or \*(FC%f\fP, whichever is shorter, with
|
|||
|
|
nonsignificant zeros suppressed
|
|||
|
|
\*(FC%G\fP like \*(FC%g\fP, but use \*(FC%E\fP instead of \*(FC%e\*(FR
|
|||
|
|
\*(FC%o\fP an unsigned octal integer
|
|||
|
|
\*(FC%u\fP an unsigned decimal integer
|
|||
|
|
\*(FC%s\fP a character string
|
|||
|
|
\*(FC%x\fP an unsigned hexadecimal integer
|
|||
|
|
\*(FC%X\fP like \*(FC%x\fP, but use \*(FCABCDEF\fP for 10\(en15
|
|||
|
|
\*(FC%%\fP A literal \*(FC%\fP; no argument is converted
|
|||
|
|
.sp .5
|
|||
|
|
.fi
|
|||
|
|
Optional, additional parameters may lie between the \*(FC%\fP
|
|||
|
|
and the control letter:
|
|||
|
|
.sp .5
|
|||
|
|
.TS
|
|||
|
|
expand;
|
|||
|
|
l lw(2.2i).
|
|||
|
|
\*(FC\-\fP T{
|
|||
|
|
left-justify the expression within its field.
|
|||
|
|
T}
|
|||
|
|
\*(FIspace\fP T{
|
|||
|
|
for numeric conversions, prefix positive values
|
|||
|
|
with a space and negative values with a
|
|||
|
|
minus sign.
|
|||
|
|
T}
|
|||
|
|
\*(FC+\fP T{
|
|||
|
|
used before the \*(FIwidth\fP modifier means to always
|
|||
|
|
supply a sign for numeric conversions, even if
|
|||
|
|
the data to be formatted is positive. The \*(FC+\fP
|
|||
|
|
overrides the space modifier.
|
|||
|
|
T}
|
|||
|
|
\*(FC#\fP T{
|
|||
|
|
use an ``alternate form'' for some control letters.
|
|||
|
|
T}
|
|||
|
|
\*(FC%o\*(FR T{
|
|||
|
|
supply a leading zero.
|
|||
|
|
T}
|
|||
|
|
\*(FC%x\*(FR, \*(FC%X\*(FR T{
|
|||
|
|
supply a leading \*(FC0x\*(FR or \*(FC0X\*(FR for a nonzero result.
|
|||
|
|
T}
|
|||
|
|
\*(FC%e\*(FR, \*(FC%E\*(FR, \*(FC%f\*(FR T{
|
|||
|
|
the result always has a decimal point.
|
|||
|
|
T}
|
|||
|
|
\*(FC%g\*(FR, \*(FC%G\*(FR T{
|
|||
|
|
trailing zeros are not removed.
|
|||
|
|
T}
|
|||
|
|
\*(FC0\fP T{
|
|||
|
|
a leading zero acts as a flag, indicating output
|
|||
|
|
should be padded with zeroes instead of spaces.
|
|||
|
|
This applies even to non-numeric output formats.
|
|||
|
|
Only has an effect when the field width is wider
|
|||
|
|
than the value to be printed.
|
|||
|
|
T}
|
|||
|
|
\*(FIwidth\fP T{
|
|||
|
|
pad the field to this width. The field is normally
|
|||
|
|
padded with spaces. If the \*(FC0\fP flag has been used,
|
|||
|
|
pad with zeroes.
|
|||
|
|
T}
|
|||
|
|
\*(FC.\fP\*(FIprec\fP T{
|
|||
|
|
precision.
|
|||
|
|
The meaning varies by control letter:
|
|||
|
|
T}
|
|||
|
|
\*(FC%d\*(FR, \*(FC%o\*(FR, \*(FC%i\*(FR,
|
|||
|
|
\*(FC%u\*(FR, \*(FC%x\*(FR, \*(FC%X\fP T{
|
|||
|
|
the minimum number of digits to print.
|
|||
|
|
T}
|
|||
|
|
\*(FC%e\*(FR, \*(FC%E\*(FR, \*(FC%f\*(FR T{
|
|||
|
|
the number of digits to print to the right of the decimal point.
|
|||
|
|
T}
|
|||
|
|
\*(FC%g\*(FR, \*(FC%G\fP T{
|
|||
|
|
the maximum number of significant digits.
|
|||
|
|
T}
|
|||
|
|
\*(FC%s\fP T{
|
|||
|
|
the maximum number of characters to print.
|
|||
|
|
T}
|
|||
|
|
.TE
|
|||
|
|
.sp .5
|
|||
|
|
.fi
|
|||
|
|
The dynamic \*(FIwidth\fP and \*(FIprec\fP capabilities of the ANSI C
|
|||
|
|
\*(FCprintf()\fP routines are supported.
|
|||
|
|
A \*(FC*\fP in place of either the \*(FIwidth\fP or \*(FIprec\fP
|
|||
|
|
specifications will cause their values to be taken from
|
|||
|
|
the argument list to \*(FCprintf\fP or \*(FCsprintf()\*(FR.\*(CX
|
|||
|
|
.EB "\s+2\f(HBPRINTF FORMATS\*(FR\s0"
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
.BT
|
|||
|
|
|
|||
|
|
.\" --- Special Filenames
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDWhen doing I/O redirection from either \*(FCprint\fP
|
|||
|
|
or \*(FCprintf\fP into a file or via \*(FCgetline\fP
|
|||
|
|
from a file, all three implementations of \*(FCawk\fP
|
|||
|
|
recognize certain special filenames internally. These filenames
|
|||
|
|
allow access to open file descriptors inherited from the
|
|||
|
|
parent process (usually the shell).
|
|||
|
|
These filenames may also be used on the command line to name data files.
|
|||
|
|
The filenames are:
|
|||
|
|
.sp .5
|
|||
|
|
.TS
|
|||
|
|
expand;
|
|||
|
|
l lw(2i).
|
|||
|
|
\*(FC"\-"\fP standard input
|
|||
|
|
\*(FC/dev/stdin\fP standard input \*(CR(not \*(MK)\*(CD
|
|||
|
|
\*(FC/dev/stdout\fP standard output
|
|||
|
|
\*(FC/dev/stderr\fP standard error output
|
|||
|
|
.TE
|
|||
|
|
.sp .5
|
|||
|
|
.fi
|
|||
|
|
\*(CBThe following names are specific to \*(GK.
|
|||
|
|
.sp .5
|
|||
|
|
.TS
|
|||
|
|
expand;
|
|||
|
|
l lw(2i).
|
|||
|
|
\*(FC/dev/fd/\^\*(FIn\*(FR T{
|
|||
|
|
file associated with the open file descriptor \*(FIn\*(FR
|
|||
|
|
T}
|
|||
|
|
.TE
|
|||
|
|
.sp .5
|
|||
|
|
.fi
|
|||
|
|
Other special filenames provide access to information about the running
|
|||
|
|
\*(FCgawk\fP process.
|
|||
|
|
Reading from these files returns a single record.
|
|||
|
|
The filenames and what they return are:\*(FR
|
|||
|
|
.sp .5
|
|||
|
|
.TS
|
|||
|
|
expand;
|
|||
|
|
l lw(2i).
|
|||
|
|
\*(FC/dev/pid\fP process ID of current process
|
|||
|
|
\*(FC/dev/ppid\fP parent process ID of current process
|
|||
|
|
\*(FC/dev/pgrpid\fP process group ID of current process
|
|||
|
|
\*(FC/dev/user\fP T{
|
|||
|
|
.nf
|
|||
|
|
a single newline-terminated record.
|
|||
|
|
The fields are separated with spaces.
|
|||
|
|
\*(FC$1\fP is the return value of \*(FIgetuid\*(FR(2),
|
|||
|
|
\*(FC$2\fP is the return value of \*(FIgeteuid\*(FR(2),
|
|||
|
|
\*(FC$3\fP is the return value of \*(FIgetgid\*(FR(2) , and
|
|||
|
|
\*(FC$4\fP is the return value of \*(FIgetegid\*(FR(2).
|
|||
|
|
.fi
|
|||
|
|
Any additional fields are the group IDs returned
|
|||
|
|
by \*(FIgetgroups\*(FR(2). Multiple groups may not be
|
|||
|
|
supported on all systems.
|
|||
|
|
T}
|
|||
|
|
.TE
|
|||
|
|
.sp .5
|
|||
|
|
.fi
|
|||
|
|
.ig
|
|||
|
|
\*(CRThese filenames are now obsolete.
|
|||
|
|
Use the \*(FCPROCINFO\fP array to obtain the information they provide.\*(CL
|
|||
|
|
..
|
|||
|
|
.\" BEGIN FOR 3.0.x
|
|||
|
|
\*(CRThese filenames will become obsolete in \*(GK 3.1.
|
|||
|
|
Be aware that you will have to change your programs.\*(CL
|
|||
|
|
.\" END FOR 3.0.x
|
|||
|
|
.EB "\s+2\f(HBSPECIAL FILENAMES\*(FR\s0"
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
.\" --- Builtin Numeric Functions
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
.TS
|
|||
|
|
expand;
|
|||
|
|
l lw(2i).
|
|||
|
|
\*(CD\*(FCatan2(\*(FIy\*(FC, \*(FIx\*(FC)\*(FR the arctangent of \*(FIy/x\fP in radians.
|
|||
|
|
\*(FCcos(\*(FIexpr\*(FC)\*(FR the cosine of \*(FIexpr\fP, which is in radians.
|
|||
|
|
\*(FCexp(\*(FIexpr\*(FC)\*(FR the exponential function (\*(FIe \*(FC^ \*(FIx\*(FR).
|
|||
|
|
\*(FCint(\*(FIexpr\*(FC)\*(FR truncates to integer.
|
|||
|
|
\*(FClog(\*(FIexpr\*(FC)\*(FR the natural logarithm function (base \*(FIe\^\*(FR).
|
|||
|
|
\*(FCrand()\fP a random number between 0 and 1.
|
|||
|
|
\*(FCsin(\*(FIexpr\*(FC)\*(FR the sine of \*(FIexpr\fP, which is in radians.
|
|||
|
|
\*(FCsqrt(\*(FIexpr\*(FC)\*(FR the square root function.
|
|||
|
|
\&\*(FCsrand(\*(FR[\*(FIexpr\^\*(FR]\*(FC)\*(FR T{
|
|||
|
|
uses \*(FIexpr\fP as a new seed for the random number
|
|||
|
|
generator. If no \*(FIexpr\fP, the time of day is used.
|
|||
|
|
Returns previous seed for the random number
|
|||
|
|
generator.\*(CX
|
|||
|
|
T}
|
|||
|
|
.TE
|
|||
|
|
.EB "\s+2\f(HBNUMERIC FUNCTIONS\*(FR\s0"
|
|||
|
|
|
|||
|
|
|
|||
|
|
.BT
|
|||
|
|
|
|||
|
|
|
|||
|
|
.\" --- Builtin String Functions
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
.in +.2i
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(CB\*(FCgensub(\*(FIr\*(FC, \*(FIs\*(FC, \*(FIh \*(FR[\*(FC, \*(FIt\*(FR]\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
search the target string
|
|||
|
|
\*(FIt\fP for matches of the regular expression \*(FIr\*(FR. If
|
|||
|
|
\*(FIh\fP is a string beginning with \*(FCg\fP or \*(FCG\*(FR,
|
|||
|
|
replace all matches of \*(FIr\fP with \*(FIs\*(FR. Otherwise, \*(FIh\fP
|
|||
|
|
is a number indicating which match of \*(FIr\fP to replace. If no
|
|||
|
|
\*(FIt\fP is supplied, \*(FC$0\fP is used instead. Within the
|
|||
|
|
replacement text \*(FIs\*(FR, the sequence \*(FC\e\*(FIn\*(FR,
|
|||
|
|
where \*(FIn\fP is a digit from 1 to 9, may be used to indicate just
|
|||
|
|
the text that matched the \*(FIn\*(FRth parenthesized subexpression.
|
|||
|
|
The sequence \*(FC\e0\fP represents the entire matched text, as does
|
|||
|
|
the character \*(FC&\*(FR. Unlike \*(FCsub()\fP and \*(FCgsub()\*(FR,
|
|||
|
|
the modified string is returned as the result of the function,
|
|||
|
|
and the original target string is \*(FInot\fP changed.\*(CD
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCgsub(\*(FIr\*(FC, \*(FIs \*(FR[\*(FC, \*(FIt\*(FR]\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
for each substring matching the
|
|||
|
|
regular expression \*(FIr\fP in the string \*(FIt\*(FR, substitute the
|
|||
|
|
string \*(FIs\*(FR, and return the number of substitutions. If
|
|||
|
|
\*(FIt\fP is not supplied, use \*(FC$0\*(FR. An \*(FC&\fP in the
|
|||
|
|
replacement text is replaced with the text that was actually matched.
|
|||
|
|
Use \*(FC\e&\fP to get a literal \*(FC&\*(FR. See \*(AM
|
|||
|
|
for a fuller discussion of the rules for \*(FC&\*(FR's and backslashes
|
|||
|
|
in the replacement text of \*(CB\*(FCgensub()\*(FR,\*(CD \*(FCsub()\*(FR
|
|||
|
|
and \*(FCgsub()\*(FR
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCindex(\*(FIs\*(FC, \*(FIt\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
returns the index of the string
|
|||
|
|
\*(FIt\fP in the string \*(FIs\*(FR, or 0 if \*(FIt\fP is not present.
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FClength(\*(FR[\*(FIs\*(FR]\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
returns the length of the string
|
|||
|
|
\*(FIs\*(FR, or the length of \*(FC$0\fP if \*(FIs\fP is not supplied.
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCmatch(\*(FIs\*(FC, \*(FIr\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
returns the position in
|
|||
|
|
\*(FIs\fP where the regular expression \*(FIr\fP occurs, or 0 if
|
|||
|
|
\*(FIr\fP is not present, and sets the values of variables
|
|||
|
|
\*(FCRSTART\fP
|
|||
|
|
and \*(FCRLENGTH\*(FR.
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCsplit(\*(FIs\*(FC, \*(FIa \*(FR[\*(FC, \*(FIr\*(FR]\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
splits the string
|
|||
|
|
\*(FIs\fP into the array \*(FIa\fP using the regular expression \*(FIr\*(FR,
|
|||
|
|
and returns the number of fields. If \*(FIr\fP is omitted, \*(FCFS\fP
|
|||
|
|
is used instead. The array \*(FIa\fP is cleared first.
|
|||
|
|
Splitting behaves identically to field splitting.
|
|||
|
|
(See \fHFields\fP, above.)
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCsprintf(\*(FIfmt\*(FC, \*(FIexpr-list\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
prints \*(FIexpr-list\fP
|
|||
|
|
according to \*(FIfmt\*(FR, and returns the resulting string.
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCsub(\*(FIr\*(FC, \*(FIs \*(FR[\*(FC, \*(FIt\*(FR]\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
just like
|
|||
|
|
\*(FCgsub()\*(FR, but only the first matching substring is replaced.
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCsubstr(\*(FIs\*(FC, \*(FIi \*(FR[\*(FC, \*(FIn\*(FR]\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
returns the at most
|
|||
|
|
\*(FIn\*(FR-character substring of \*(FIs\fP starting at \*(FIi\*(FR.
|
|||
|
|
If \*(FIn\fP is omitted, the rest of \*(FIs\fP is used.
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCtolower(\*(FIstr\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
returns a copy of the string \*(FIstr\*(FR,
|
|||
|
|
with all the upper-case characters in \*(FIstr\fP translated to their
|
|||
|
|
corresponding lower-case counterparts. Non-alphabetic characters are
|
|||
|
|
left unchanged.
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCtoupper(\*(FIstr\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
returns a copy of the string \*(FIstr\*(FR,
|
|||
|
|
with all the lower-case characters in \*(FIstr\fP translated to their
|
|||
|
|
corresponding upper-case counterparts. Non-alphabetic characters are
|
|||
|
|
left unchanged.\*(CX
|
|||
|
|
.in -.2i
|
|||
|
|
.EB "\s+2\f(HBSTRING FUNCTIONS\*(FR\s0"
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
.BT
|
|||
|
|
|
|||
|
|
|
|||
|
|
.\" --- Builtin Time Functions
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CD\*(GK
|
|||
|
|
provides the following functions for obtaining time stamps and
|
|||
|
|
formatting them.
|
|||
|
|
.sp .5
|
|||
|
|
.fi
|
|||
|
|
.in +.2i
|
|||
|
|
.ig
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCmktime(\*(FIdatespec\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
turns \*(FIdatespec\fP into a time
|
|||
|
|
stamp of the same form as returned by \*(FCsystime()\*(FR.
|
|||
|
|
The \*(FIdatespec\fP is a string of the form
|
|||
|
|
\*(FC"\*(FIYYYY MM DD HH MM SS\*(FC"\*(FR.
|
|||
|
|
..
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCstrftime(\*(FR[\*(FIformat \*(FR[\*(FC, \*(FItimestamp\*(FR]]\*(FC)\*(FR
|
|||
|
|
.br
|
|||
|
|
formats \*(FItimestamp\fP
|
|||
|
|
according to the specification in \*(FIformat\*(FR. The
|
|||
|
|
\*(FItimestamp\fP should be of the same form as returned by
|
|||
|
|
\*(FCsystime()\*(FR.
|
|||
|
|
If \*(FItimestamp\fP is missing, the current time of day is used. If
|
|||
|
|
\*(FIformat\fP is missing, a default format equivalent to the output
|
|||
|
|
of \*(FIdate\*(FR(1) will be used.
|
|||
|
|
.ti -.2i
|
|||
|
|
\*(FCsystime()\fP
|
|||
|
|
.br
|
|||
|
|
returns the current time of day as the number of
|
|||
|
|
seconds since the Epoch.\*(CB
|
|||
|
|
.in -.2i
|
|||
|
|
.EB "\s+2\f(HBTIME FUNCTIONS (\*(GK\f(HB)\*(FR\s0"
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
.\" --- User-defined Functions
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDFunctions in AWK are defined as follows:
|
|||
|
|
.sp .5
|
|||
|
|
.nf
|
|||
|
|
\*(FCfunction \*(FIname\*(FC(\*(FIparameter list\*(FC)
|
|||
|
|
{
|
|||
|
|
\*(FIstatements
|
|||
|
|
\*(FC}\*(FR
|
|||
|
|
.sp .5
|
|||
|
|
.fi
|
|||
|
|
Functions are executed when they are called from within expressions
|
|||
|
|
in either patterns or actions. Actual parameters supplied in the function
|
|||
|
|
call instantiate the formal parameters declared in the function.
|
|||
|
|
Arrays are passed by reference, other variables are passed by value.
|
|||
|
|
.sp .5
|
|||
|
|
Local variables are declared as extra parameters
|
|||
|
|
in the parameter list. The convention is to separate local variables from
|
|||
|
|
real parameters by extra spaces in the parameter list. For example:
|
|||
|
|
.sp .5
|
|||
|
|
.nf
|
|||
|
|
\*(FC# a & b are local
|
|||
|
|
function f(p, q, a, b)
|
|||
|
|
{
|
|||
|
|
\&.....
|
|||
|
|
}
|
|||
|
|
.sp .3
|
|||
|
|
/abc/ { ... ; f(1, 2) ; ... }\*(FR
|
|||
|
|
.fi
|
|||
|
|
.sp .5
|
|||
|
|
The left parenthesis in a function call is required
|
|||
|
|
to immediately follow the function name
|
|||
|
|
without any intervening white space.
|
|||
|
|
This is to avoid a syntactic ambiguity with the concatenation operator.
|
|||
|
|
This restriction does not apply to the built-in functions.
|
|||
|
|
.sp .5
|
|||
|
|
Functions may call each other and may be recursive.
|
|||
|
|
Function parameters used as local variables are initialized
|
|||
|
|
to the null string and the number zero upon function invocation.
|
|||
|
|
.sp .5
|
|||
|
|
Use \*(FCreturn\fP to return a value from a function. The return value
|
|||
|
|
is undefined if no value is provided, or if the function returns by
|
|||
|
|
``falling off'' the end.
|
|||
|
|
.sp .5
|
|||
|
|
\*(CLThe word
|
|||
|
|
\*(FCfunc\fP
|
|||
|
|
may be used in place of
|
|||
|
|
\*(FCfunction\*(FR.
|
|||
|
|
\*(CRNote: This usage is deprecated.\*(CX
|
|||
|
|
.EB "\s+2\f(HBUSER-DEFINED FUNCTIONS\*(FR\s0"
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
.\" --- Bug Reports
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDIf you find a bug in this reference card, please report it via electronic
|
|||
|
|
mail to \*(FCarnold@gnu.org\*(FR.\*(CX
|
|||
|
|
.EB "\s+2\f(HBBUG REPORTS\*(FR\s0"
|
|||
|
|
|
|||
|
|
.BT
|
|||
|
|
|
|||
|
|
.\" --- Environment Variables
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDThe environment variable \*(FCAWKPATH\fP specifies a search path to use
|
|||
|
|
when finding source files named with the \*(FC\-f\fP
|
|||
|
|
option.
|
|||
|
|
The default path is
|
|||
|
|
\*(FC".:/usr/local/share/awk"\*(FR,
|
|||
|
|
if this variable does not exist.
|
|||
|
|
(The actual directory may vary,
|
|||
|
|
depending upon how \*(GK was built and installed.)
|
|||
|
|
If a file name given to the \*(FC\-f\fP option contains a ``/'' character,
|
|||
|
|
no path search is performed.
|
|||
|
|
.sp .5
|
|||
|
|
If \*(FCPOSIXLY_CORRECT\fP exists in the environment, then \*(GK
|
|||
|
|
behaves exactly as if \*(FC\-\^\-posix\fP had been specified on the
|
|||
|
|
command line.\*(CB
|
|||
|
|
.EB "\s+2\f(HBENVIRONMENT VARIABLES (\*(GK\f(HB)\*(FR\s0"
|
|||
|
|
|
|||
|
|
.\" --- Historical Features
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CD\*(GK supports two features of historical AWK implementations.
|
|||
|
|
First, it is possible to call the \*(FClength()\fP
|
|||
|
|
built-in function not only with no argument, but even without parentheses.
|
|||
|
|
This feature is marked as ``deprecated'' in the POSIX standard, and \*(GK
|
|||
|
|
will issue a warning about its use if \*(FC\-\^\-lint\fP
|
|||
|
|
is specified on the command line.
|
|||
|
|
.sp .5
|
|||
|
|
The other feature is the use of \*(FCcontinue\fP
|
|||
|
|
or \*(FCbreak\fP statements outside the body of a
|
|||
|
|
\*(FCwhile\*(FR, \*(FCfor\*(FR, or \*(FCdo\fP loop.
|
|||
|
|
Historical AWK implementations have treated such usage as
|
|||
|
|
equivalent to the \*(FCnext\fP statement.
|
|||
|
|
\*(GK will support this usage if \*(FC\-\^\-traditional\fP
|
|||
|
|
has been specified.\*(CB
|
|||
|
|
.EB "\s+2\f(HBHISTORICAL FEATURES (\*(GK\f(HB)\*(FR\s0"
|
|||
|
|
|
|||
|
|
|
|||
|
|
.\" --- FTP Information
|
|||
|
|
.ES
|
|||
|
|
.nf
|
|||
|
|
\*(CDHost: \*(FCgnudist.gnu.org\*(FR
|
|||
|
|
File: \*(FC/gnu/gawk/gawk-3.0.6.tar.gz\fP
|
|||
|
|
.in +.2i
|
|||
|
|
.fi
|
|||
|
|
GNU \*(AK (\*(GK). There may be a later version.
|
|||
|
|
.in -.2i
|
|||
|
|
.nf
|
|||
|
|
.sp .5
|
|||
|
|
Host: \*(FCnetlib.bell-labs.com\*(FR
|
|||
|
|
File: \*(FC/netlib/research/awk.bundle.gz\fP
|
|||
|
|
.in +.2i
|
|||
|
|
.fi
|
|||
|
|
\*(NK. This version requires an ANSI C compiler;
|
|||
|
|
GCC (the GNU C compiler) works well.
|
|||
|
|
.in -.2i
|
|||
|
|
.nf
|
|||
|
|
.sp .5
|
|||
|
|
Host: \*(FCftp.whidbey.net\*(FR
|
|||
|
|
File: \*(FC/pub/brennan/mawk1.3.3.tar.gz\fP
|
|||
|
|
.in +.2i
|
|||
|
|
.fi
|
|||
|
|
Michael Brennan's \*(MK. There may be a newer version.\*(CX
|
|||
|
|
.in -.2i
|
|||
|
|
.EB "\s+2\f(HBFTP INFORMATION\*(FR\s0"
|
|||
|
|
|
|||
|
|
.\" --- Copying Permissions
|
|||
|
|
.ES
|
|||
|
|
.fi
|
|||
|
|
\*(CDCopyright \(co 1996-2000 Free Software Foundation, Inc.
|
|||
|
|
.sp .5
|
|||
|
|
Permission is granted to make and distribute verbatim copies of this
|
|||
|
|
reference card provided the copyright notice and this permission notice
|
|||
|
|
are preserved on all copies.
|
|||
|
|
.sp .5
|
|||
|
|
Permission is granted to copy and distribute modified versions of this
|
|||
|
|
reference card under the conditions for verbatim copying, provided that
|
|||
|
|
the entire resulting derived work is distributed under the terms of a
|
|||
|
|
permission notice identical to this one.
|
|||
|
|
.sp .5
|
|||
|
|
Permission is granted to copy and distribute translations of this
|
|||
|
|
reference card into another language, under the above conditions for
|
|||
|
|
modified versions, except that this permission notice may be stated in a
|
|||
|
|
translation approved by the Foundation.\*(CX
|
|||
|
|
.EB "\s+2\f(HBCOPYING PERMISSIONS\*(FR\s0"
|
|||
|
|
.BT
|