diff options
Diffstat (limited to 'awk.1')
| -rw-r--r-- | awk.1 | 160 |
1 files changed, 96 insertions, 64 deletions
@@ -7,7 +7,6 @@ .fi .ft 1 .. -awk .TH AWK 1 .CT 1 files prog_other .SH NAME @@ -36,7 +35,7 @@ awk \- pattern-directed scanning and processing language scans each input .I file for lines that match any of a set of patterns specified literally in -.IR prog +.I prog or in one or more files specified as .B \-f @@ -53,7 +52,7 @@ The file name .B \- means the standard input. Any -.IR file +.I file of the form .I var=value is treated as an assignment, not a filename, @@ -70,12 +69,12 @@ any number of options may be present. The .B \-F -.IR fs +.I fs option defines the input field separator to be the regular expression -.IR fs. +.IR fs . .PP An input line is normally made up of fields separated by white space, -or by regular expression +or by the regular expression .BR FS . The fields are denoted .BR $1 , @@ -87,7 +86,7 @@ If .BR FS is null, the input line is split into one field per character. .PP -A pattern-action statement has the form +A pattern-action statement has the form: .IP .IB pattern " { " action " } .PP @@ -101,7 +100,7 @@ An action is a sequence of statements. A statement can be one of the following: .PP .EX -.ta \w'\f(CWdelete array[expression]'u +.ta \w'\f(CWdelete array[expression]\fR'u .RS .nf .ft CW @@ -145,7 +144,7 @@ The operators are also available in expressions. Variables may be scalars, array elements (denoted -.IB x [ i ] ) +.IB x [ i ] \fR) or fields. Variables are initialized to the null string. Array subscripts may be any string, @@ -161,11 +160,11 @@ The .B print statement prints its arguments on the standard output (or on a file if -.BI > file +.BI > " file or -.BI >> file +.BI >> " file is present or on a pipe if -.BI | cmd +.BI | " cmd is present), separated by the current output field separator, and terminated by the output record separator. .I file @@ -176,9 +175,10 @@ identical string values in different statements denote the same open file. The .B printf -statement formats its expression list according to the format +statement formats its expression list according to the +.I format (see -.IR printf (3)) . +.IR printf (3)). The built-in function .BI close( expr ) closes the file or pipe @@ -189,13 +189,13 @@ flushes any buffered output for the file or pipe .IR expr . .PP The mathematical functions +.BR atan2 , +.BR cos , .BR exp , .BR log , -.BR sqrt , .BR sin , -.BR cos , and -.BR atan2 +.B sqrt are built in. Other built-in functions: .TF length @@ -203,7 +203,8 @@ Other built-in functions: .B length the length of its argument taken as a string, -or of +number of elements in an array for an array argument, +or length of .B $0 if no argument. .TP @@ -218,14 +219,18 @@ and returns the previous seed. .B int truncates to an integer value .TP -.BI substr( s , " m" , " n\fB) +\fBsubstr(\fIs\fB, \fIm\fR [\fB, \fIn\^\fR]\fB)\fR the .IR n -character substring of .I s that begins at position -.IR m +.I m counted from 1. +If no +.IR m , +use the rest of the string +.I .TP .BI index( s , " t" ) the position in @@ -246,14 +251,14 @@ and .B RLENGTH are set to the position and length of the matched string. .TP -.BI split( s , " a" , " fs\fB) +\fBsplit(\fIs\fB, \fIa \fR[\fB, \fIfs\^\fR]\fB)\fR splits the string .I s into array elements -.IB a [1] , -.IB a [2] , +.IB a [1] \fR, +.IB a [2] \fR, \&..., -.IB a [ n ] , +.IB a [ n ] \fR, and returns .IR n . The separation is done with the regular expression @@ -266,7 +271,7 @@ is not given. An empty string as field separator splits the string into one array element per character. .TP -.BI sub( r , " t" , " s\fB) +\fBsub(\fIr\fB, \fIt \fR[, \fIs\^\fR]\fB) substitutes .I t for the first occurrence of the regular expression @@ -279,7 +284,7 @@ is not given, .B $0 is used. .TP -.B gsub +\fBgsub(\fIr\fB, \fIt \fR[, \fIs\^\fR]\fB) same as .B sub except that all occurrences of the regular expression @@ -289,18 +294,28 @@ and .B gsub return the number of replacements. .TP -.BI sprintf( fmt , " expr" , " ...\fB ) +.BI sprintf( fmt , " expr" , " ...\fB) the string resulting from formatting .I expr ... according to the .IR printf (3) format -.I fmt +.IR fmt . .TP .BI system( cmd ) executes .I cmd -and returns its exit status +and returns its exit status. This will be \-1 upon error, +.IR cmd 's +exit status upon a normal exit, +256 + +.I sig +upon death-by-signal, where +.I sig +is the number of the murdering signal, +or 512 + +.I sig +if there was a core dump. .TP .BI tolower( str ) returns a copy of @@ -321,7 +336,7 @@ sets .B $0 to the next input record from the current input file; .B getline -.BI < file +.BI < " file sets .B $0 to the next record from @@ -359,7 +374,7 @@ Isolated regular expressions in a pattern apply to the entire line. Regular expressions may also occur in relational expressions, using the operators -.BR ~ +.B ~ and .BR !~ . .BI / re / @@ -383,8 +398,12 @@ A relational expression is one of the following: .br .BI ( expr , expr,... ") in " array-name .PP -where a relop is any of the six relational operators in C, -and a matchop is either +where a +.I relop +is any of the six relational operators in C, +and a +.I matchop +is either .B ~ (matches) or @@ -405,57 +424,68 @@ and after the last. and .B END do not combine with other patterns. +They may appear multiple times in a program and execute +in the order they are read by +.IR awk . .PP Variable names with special meanings: .TF FILENAME .TP +.B ARGC +argument count, assignable. +.TP +.B ARGV +argument array, assignable; +non-null members are taken as filenames. +.TP .B CONVFMT conversion format used when converting numbers (default -.BR "%.6g" ) +.BR "%.6g" ). +.TP +.B ENVIRON +array of environment variables; subscripts are names. +.TP +.B FILENAME +the name of the current input file. +.TP +.B FNR +ordinal number of the current record in the current file. .TP .B FS regular expression used to separate fields; also settable by option -.BI \-F fs. +.BI \-F fs\fR. .TP .BR NF -number of fields in the current record +number of fields in the current record. .TP .B NR -ordinal number of the current record -.TP -.B FNR -ordinal number of the current record in the current file -.TP -.B FILENAME -the name of the current input file +ordinal number of the current record. .TP -.B RS -input record separator (default newline) +.B OFMT +output format for numbers (default +.BR "%.6g" ). .TP .B OFS -output field separator (default blank) +output field separator (default space). .TP .B ORS -output record separator (default newline) +output record separator (default newline). .TP -.B OFMT -output format for numbers (default -.BR "%.6g" ) -.TP -.B SUBSEP -separates multiple subscripts (default 034) +.B RLENGTH +the length of a string matched by +.BR match . .TP -.B ARGC -argument count, assignable +.B RS +input record separator (default newline). .TP -.B ARGV -argument array, assignable; -non-null members are taken as filenames +.B RSTART +the start position of a string matched by +.BR match . .TP -.B ENVIRON -array of environment variables; subscripts are names. +.B SUBSEP +separates multiple subscripts (default 034). .PD .PP Functions may be defined (at the position of a pattern-action statement) thus: @@ -486,7 +516,7 @@ BEGIN { FS = ",[ \et]*|[ \et]+" } .EE .ns .IP -Same, with input fields separated by comma and/or blanks and tabs. +Same, with input fields separated by comma and/or spaces and tabs. .PP .EX .nf @@ -512,13 +542,13 @@ BEGIN { # Simulate echo(1) .fi .EE .SH SEE ALSO +.IR grep (1), .IR lex (1), .IR sed (1) .br A. V. Aho, B. W. Kernighan, P. J. Weinberger, -.I -The AWK Programming Language, -Addison-Wesley, 1988. ISBN 0-201-07981-X +.IR "The AWK Programming Language" , +Addison-Wesley, 1988. ISBN 0-201-07981-X. .SH BUGS There are no explicit conversions between numbers and strings. To force an expression to be treated as a number add 0 to it; @@ -527,3 +557,5 @@ to force it to be treated as a string concatenate .br The scope rules for variables in functions are a botch; the syntax is worse. +.br +Only eight-bit characters sets are handled correctly. |