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Portions of this text are reprinted and reproduced in electronic form in the Sun OS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html. .\" This notice shall appear on any product containing this material. .\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License. .\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing. See the License for the specific language governing permissions and limitations under the License. .\" When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] .TH awk 1 "22 Jun 2005" "SunOS 5.11" "User Commands" .SH NAME awk \- pattern scanning and processing language .SH SYNOPSIS .LP .nf \fB/usr/bin/awk\fR [\fB-f\fR \fIprogfile\fR] [\fB-F\fIc\fR\fR] [' \fIprog\fR '] [\fIparameters\fR] [\fIfilename\fR]... .fi .LP .nf \fB/usr/xpg4/bin/awk\fR [\fB-F\fR\fIcERE\fR] [\fB-v\fR \fIassignment\fR]... \fI\&'program'\fR \fB-f\fR \fIprogfile\fR... [\fIargument\fR]... .fi .SH DESCRIPTION .sp .LP The \fB/usr/xpg4/bin/awk\fR utility is described on the \fBnawk\fR(1) manual page. .sp .LP The \fB/usr/bin/awk\fR utility scans each input \fIfilename\fR for lines that match any of a set of patterns specified in \fIprog\fR. The \fIprog\fR string must be enclosed in single quotes (\fB a\'\fR) to protect it from the shell. For each pattern in \fIprog\fR there can be an associated action performed when a line of a \fIfilename\fR matches the pattern. The set of pattern-action statements can appear literally as \fIprog\fR or in a file specified with the \fB-f\fR\fI progfile\fR option. Input files are read in order; if there are no files, the standard input is read. The file name \fB\&'\(mi'\fR means the standard input. .SH OPTIONS .sp .LP The following options are supported: .sp .ne 2 .mk .na \fB\fB-f\fR\fI progfile\fR \fR .ad .RS 16n .rt \fBawk\fR uses the set of patterns it reads from \fIprogfile\fR. .RE .sp .ne 2 .mk .na \fB\fB-F\fR\fIc\fR \fR .ad .RS 16n .rt Uses the character \fIc\fR as the field separator (FS) character. See the discussion of \fBFS\fR below. .RE .SH USAGE .SS "Input Lines" .sp .LP Each input line is matched against the pattern portion of every pattern-action statement; the associated action is performed for each matched pattern. Any \fIfilename\fR of the form \fIvar=value\fR is treated as an assignment, not a filename, and is executed at the time it would have been opened if it were a filename. \fIVariables\fR assigned in this manner are not available inside a \fBBEGIN\fR rule, and are assigned after previously specified files have been read. .sp .LP An input line is normally made up of fields separated by white spaces. (This default can be changed by using the \fBFS\fR built-in variable or the \fB-F\fR\fIc\fR option.) The default is to ignore leading blanks and to separate fields by blanks and/or tab characters. However, if \fBFS\fR is assigned a value that does not include any of the white spaces, then leading blanks are not ignored. The fields are denoted \fB$1\fR, \fB$2\fR, \fB\&.\|.\|.\fR\|; \fB$0\fR refers to the entire line. .SS "Pattern-action Statements" .sp .LP A pattern-action statement has the form: .sp .in +2 .nf \fIpattern\fR\fB { \fR\fIaction\fR\fB } \fR .fi .in -2 .sp .sp .LP Either pattern or action can be omitted. If there is no action, the matching line is printed. If there is no pattern, the action is performed on every input line. Pattern-action statements are separated by newlines or semicolons. .sp .LP Patterns are arbitrary Boolean combinations ( \fB!\fR, ||, \fB&&\fR, and parentheses) of relational expressions and regular expressions. A relational expression is one of the following: .sp .in +2 .nf \fIexpression relop expression expression matchop regular_expression\fR .fi .in -2 .sp .LP where a \fIrelop\fR is any of the six relational operators in C, and a \fImatchop\fR is either \fB~\fR (contains) or \fB!~\fR (does not contain). An \fIexpression\fR is an arithmetic expression, a relational expression, the special expression .sp .in +2 .nf \fIvar \fRin \fIarray\fR .fi .in -2 .sp .LP or a Boolean combination of these. .sp .LP Regular expressions are as in \fBegrep\fR(1). In patterns they must be surrounded by slashes. Isolated regular expressions in a pattern apply to the entire line. Regular expressions can also occur in relational expressions. A pattern can consist of two patterns separated by a comma; in this case, the action is performed for all lines between the occurrence of the first pattern to the occurrence of the second pattern. .sp .LP The special patterns \fBBEGIN\fR and \fBEND\fR can be used to capture control before the first input line has been read and after the last input line has been read respectively. These keywords do not combine with any other patterns. .SS "Built-in Variables" .sp .LP Built-in variables include: .sp .ne 2 .mk .na \fB\fBFILENAME\fR \fR .ad .RS 13n .rt name of the current input file .RE .sp .ne 2 .mk .na \fB\fBFS\fR \fR .ad .RS 13n .rt input field separator regular expression (default blank and tab) .RE .sp .ne 2 .mk .na \fB\fBNF\fR \fR .ad .RS 13n .rt number of fields in the current record .RE .sp .ne 2 .mk .na \fB\fBNR\fR \fR .ad .RS 13n .rt ordinal number of the current record .RE .sp .ne 2 .mk .na \fB\fBOFMT\fR \fR .ad .RS 13n .rt output format for numbers (default \fB%.6g\fR) .RE .sp .ne 2 .mk .na \fB\fBOFS\fR \fR .ad .RS 13n .rt output field separator (default blank) .RE .sp .ne 2 .mk .na \fB\fBORS\fR \fR .ad .RS 13n .rt output record separator (default new-line) .RE .sp .ne 2 .mk .na \fB\fBRS\fR \fR .ad .RS 13n .rt input record separator (default new-line) .RE .sp .LP An action is a sequence of statements. A statement can be one of the following: .sp .in +2 .nf if ( \fIexpression\fR ) \fIstatement\fR [ else \fIstatement\fR ] while ( \fIexpression\fR ) \fIstatement\fR do \fIstatement\fR while ( \fIexpression\fR ) for ( \fIexpression\fR ; \fIexpression\fR ; \fIexpression\fR ) \fIstatement\fR for ( \fIvar\fR in \fIarray\fR ) \fIstatement\fR break continue { [ \fIstatement\fR ] .\|.\|. } \fIexpression\fR # commonly variable = expression print [ \fIexpression-list\fR ] [ >\fIexpression\fR ] printf format [ ,\fIexpression-list\fR ] [ >\fIexpression\fR ] next # skip remaining patterns on this input line exit [expr] # skip the rest of the input; exit status is expr .fi .in -2 .sp .LP Statements are terminated by semicolons, newlines, or right braces. An empty expression-list stands for the whole input line. Expressions take on string or numeric values as appropriate, and are built using the operators \fB+\fR, \fB\(mi\fR, \fB*\fR, \fB/\fR, \fB%\fR, \fB^\fR and concatenation (indicated by a blank). The operators \fB++\fR, \fB\(mi\(mi\fR, \fB+=\fR, \fB\(mi=\fR, \fB*=\fR, \fB/=\fR, \fB%=\fR, \fB^=\fR, \fB>\fR, \fB>=\fR, \fB<\fR, \fB<=\fR, \fB==\fR, \fB!=\fR, and \fB?:\fR are also available in expressions. Variables can be scalars, array elements (denoted x[i]), or fields. Variables are initialized to the null string or zero. Array subscripts can be any string, not necessarily numeric; this allows for a form of associative memory. String constants are quoted (\fB""\fR), with the usual C escapes recognized within. .sp .LP The \fBprint\fR statement prints its arguments on the standard output, or on a file if \fB>\fR\fIexpression\fR is present, or on a pipe if '\fB|\fR\fIcmd\fR' is present. The output resulted from the print statement is terminated by the output record separator with each argument separated by the current output field separator. The \fBprintf\fR statement formats its expression list according to the format (see \fBprintf\fR(3C)). .SS "Built-in Functions" .sp .LP The arithmetic functions are as follows: .sp .ne 2 .mk .na \fB\fBcos\fR(\fIx\fR)\fR .ad .RS 11n .rt Return cosine of \fIx\fR, where \fIx\fR is in radians. (In \fB/usr/xpg4/bin/awk\fR only. See \fBnawk\fR(1).) .RE .sp .ne 2 .mk .na \fB\fBsin\fR(\fIx\fR)\fR .ad .RS 11n .rt Return sine of \fIx\fR, where \fIx\fR is in radians. (In \fB/usr/xpg4/bin/awk\fR only. See \fBnawk\fR(1).) .RE .sp .ne 2 .mk .na \fB\fBexp\fR(\fIx\fR)\fR .ad .RS 11n .rt Return the exponential function of \fIx\fR. .RE .sp .ne 2 .mk .na \fB\fBlog\fR(\fIx\fR)\fR .ad .RS 11n .rt Return the natural logarithm of \fIx\fR. .RE .sp .ne 2 .mk .na \fB\fBsqrt\fR(\fIx\fR)\fR .ad .RS 11n .rt Return the square root of \fIx\fR. .RE .sp .ne 2 .mk .na \fB\fBint\fR(\fIx\fR)\fR .ad .RS 11n .rt Truncate its argument to an integer. It is truncated toward \fB0\fR when \fIx\fR >\fB 0\fR. .RE .sp .LP The string functions are as follows: .sp .ne 2 .mk .na \fB\fBindex(\fR\fIs\fR\fB, \fR\fIt\fR\fB)\fR\fR .ad .sp .6 .RS 4n Return the position in string \fIs\fR where string \fIt\fR first occurs, or \fB0\fR if it does not occur at all. .RE .sp .ne 2 .mk .na \fB\fBint(\fR\fIs\fR\fB)\fR\fR .ad .sp .6 .RS 4n truncates \fIs\fR to an integer value. If \fIs\fR is not specified, $0 is used. .RE .sp .ne 2 .mk .na \fB\fBlength(\fR\fIs\fR\fB)\fR\fR .ad .sp .6 .RS 4n Return the length of its argument taken as a string, or of the whole line if there is no argument. .RE .sp .ne 2 .mk .na \fB\fBsplit(\fR\fIs\fR, \fIa\fR, \fIfs\fR\fB)\fR\fR .ad .sp .6 .RS 4n Split the string \fIs\fR into array elements \fIa\fR[\fI1\fR], \fIa\fR[\fI2\fR], \|.\|.\|. \fIa\fR[\fIn\fR], and returns \fIn\fR. The separation is done with the regular expression \fIfs\fR or with the field separator \fBFS\fR if \fIfs\fR is not given. .RE .sp .ne 2 .mk .na \fB\fBsprintf(\fR\fIfmt\fR, \fIexpr\fR, \fIexpr\fR,\|.\|.\|.\|\fB)\fR\fR .ad .sp .6 .RS 4n Format the expressions according to the \fBprintf\fR(3C) format given by \fIfmt\fR and returns the resulting string. .RE .sp .ne 2 .mk .na \fB\fBsubstr(\fR\fIs\fR, \fIm\fR, \fIn\fR\fB)\fR\fR .ad .sp .6 .RS 4n returns the \fIn\fR-character substring of \fIs\fR that begins at position \fIm\fR. .RE .sp .LP The input/output function is as follows: .sp .ne 2 .mk .na \fB\fBgetline\fR\fR .ad .RS 11n .rt Set \fB$0\fR to the next input record from the current input file. \fBgetline\fR returns \fB1\fR for successful input, \fB0\fR for end of file, and \fB\(mi1\fR for an error. .RE .SS "Large File Behavior" .sp .LP See \fBlargefile\fR(5) for the description of the behavior of \fBawk\fR when encountering files greater than or equal to 2 Gbyte ( 2^31 bytes). .SH EXAMPLES .LP \fBExample 1 \fRPrinting Lines Longer Than 72 Characters .sp .LP The following example is an \fBawk\fR script that can be executed by an \fBawk -f examplescript\fR style command. It prints lines longer than seventy two characters: .sp .in +2 .nf \fBlength > 72\fR .fi .in -2 .sp .LP \fBExample 2 \fRPrinting Fields in Opposite Order .sp .LP The following example is an \fBawk\fR script that can be executed by an \fBawk -f examplescript\fR style command. It prints the first two fields in opposite order: .sp .in +2 .nf \fB{ print $2, $1 }\fR .fi .in -2 .sp .LP \fBExample 3 \fRPrinting Fields in Opposite Order with the Input Fields Separated .sp .LP The following example is an \fBawk\fR script that can be executed by an \fBawk -f examplescript\fR style command. It prints the first two input fields in opposite order, separated by a comma, blanks or tabs: .sp .in +2 .nf \fBBEGIN { FS = ",[ \et]*|[ \et]+" } { print $2, $1 }\fR .fi .in -2 .sp .LP \fBExample 4 \fRAdding Up the First Column, Printing the Sum and Average .sp .LP The following example is an \fBawk\fR script that can be executed by an \fBawk -f examplescript\fR style command. It adds up the first column, and prints the sum and average: .sp .in +2 .nf \fB{ s += $1 } END { print "sum is", s, " average is", s/NR }\fR .fi .in -2 .sp .LP \fBExample 5 \fRPrinting Fields in Reverse Order .sp .LP The following example is an \fBawk\fR script that can be executed by an \fBawk -f examplescript\fR style command. It prints fields in reverse order: .sp .in +2 .nf \fB{ for (i = NF; i > 0; \(mi\(mii) print $i }\fR .fi .in -2 .sp .LP \fBExample 6 \fRPrinting All lines Between \fBstart/stop\fR Pairs .sp .LP The following example is an \fBawk\fR script that can be executed by an \fBawk -f examplescript\fR style command. It prints all lines between start/stop pairs. .sp .in +2 .nf \fB/start/, /stop/\fR .fi .in -2 .sp .LP \fBExample 7 \fRPrinting All Lines Whose First Field is Different from the Previous One .sp .LP The following example is an \fBawk\fR script that can be executed by an \fBawk -f examplescript\fR style command. It prints all lines whose first field is different from the previous one. .sp .in +2 .nf \fB$1 != prev { print; prev = $1 }\fR .fi .in -2 .sp .LP \fBExample 8 \fRPrinting a File and Filling in Page numbers .sp .LP The following example is an \fBawk\fR script that can be executed by an \fBawk -f examplescript\fR style command. It prints a file and fills in page numbers starting at 5: .sp .in +2 .nf \fB/Page/ { $2 = n++; } { print }\fR .fi .in -2 .sp .LP \fBExample 9 \fRPrinting a File and Numbering Its Pages .sp .LP Assuming this program is in a file named \fBprog\fR, the following example prints the file \fBinput\fR numbering its pages starting at \fB5\fR: .sp .in +2 .nf example% \fBawk -f prog n=5 input\fR .fi .in -2 .sp .SH ENVIRONMENT VARIABLES .sp .LP See \fBenviron\fR(5) for descriptions of the following environment variables that affect the execution of \fBawk\fR: \fBLANG\fR, \fBLC_ALL\fR, \fBLC_COLLATE\fR, \fBLC_CTYPE\fR, \fBLC_MESSAGES\fR, \fBNLSPATH\fR, and \fBPATH\fR. .sp .ne 2 .mk .na \fB\fBLC_NUMERIC\fR\fR .ad .RS 14n .rt Determine the radix character used when interpreting numeric input, performing conversions between numeric and string values and formatting numeric output. Regardless of locale, the period character (the decimal-point character of the POSIX locale) is the decimal-point character recognized in processing \fBawk\fR programs (including assignments in command-line arguments). .RE .SH ATTRIBUTES .sp .LP See \fBattributes\fR(5) for descriptions of the following attributes: .SS "/usr/bin/awk" .sp .sp .TS tab() box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) . ATTRIBUTE TYPEATTRIBUTE VALUE _ CSINot Enabled .TE .SS "/usr/xpg4/bin/awk" .sp .sp .TS tab() box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) . ATTRIBUTE TYPEATTRIBUTE VALUE _ CSIEnabled _ Interface StabilityStandard .TE .SH SEE ALSO .sp .LP \fBegrep\fR(1), \fBgrep\fR(1), \fBnawk\fR(1), \fBsed\fR(1), \fBprintf\fR(3C), \fBattributes\fR(5), \fBenviron\fR(5), \fBlargefile\fR(5), \fBstandards\fR(5) .SH NOTES .sp .LP Input white space is not preserved on output if fields are involved. .sp .LP There are no explicit conversions between numbers and strings. To force an expression to be treated as a number, add \fB0\fR to it. To force an expression to be treated as a string, concatenate the null string (\fB""\fR) to it.