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diff --git a/static/unix-v10/man1/awk.1 b/static/unix-v10/man1/awk.1 new file mode 100644 index 00000000..7ac74960 --- /dev/null +++ b/static/unix-v10/man1/awk.1 @@ -0,0 +1,452 @@ +.TH AWK 1 +.CT 1 files prog_other +.SH NAME +awk \- pattern-directed scanning and processing language +.SH SYNOPSIS +.B awk +[ +.BI -F fs +] +[ +.I prog +] +[ +.I file ... +] +.SH DESCRIPTION +.I Awk +scans each input +.I file +for lines that match any of a set of patterns specified literally in +.IR prog +or in a file +specified as +.B -f +.IR file . +With each pattern +there can be an associated action that will be performed +when a line of a +.I file +matches the pattern. +Each line is matched against the +pattern portion of every pattern-action statement; +the associated action is performed for each matched pattern. +The file name +.L - +means the standard input. +Any +.IR file +of the form +.I var=value +is treated as an assignment, not a filename. +.PP +An input line is made up of fields separated by white space, +or by regular expression +.BR FS . +The fields are denoted +.BR $1 , +.BR $2 , +\&...; +.B $0 +refers to the entire line. +.PP +A pattern-action statement has the form +.IP +.IB pattern " { " action " } +.PP +A missing +.BI { " action " } +means print the line; +a missing pattern always matches. +Pattern-action statements are separated by newlines or semicolons. +.PP +An action is a sequence of statements. +A statement can be one of the following: +.PP +.EX +.ta \w'\f5delete array[expression]'u +if(\fI expression \fP)\fI statement \fP\fR[ \fPelse\fI statement \fP\fR]\fP +while(\fI expression \fP)\fI statement\fP +for(\fI expression \fP;\fI expression \fP;\fI expression \fP)\fI statement\fP +for(\fI var \fPin\fI array \fP)\fI statement\fP +do\fI statement \fPwhile(\fI expression \fP) +break +continue +{\fR [\fP\fI statement ... \fP\fR] \fP} +\fIexpression\fP #\fR commonly\fP\fI var = expression\fP +print\fR [ \fP\fIexpression-list \fP\fR] \fP\fR[ \fP>\fI expression \fP\fR]\fP +printf\fI format \fP\fR[ \fP,\fI expression-list \fP\fR] \fP\fR[ \fP>\fI expression \fP\fR]\fP +return\fR [ \fP\fIexpression \fP\fR]\fP +next #\fR skip remaining patterns on this input line\fP +delete\fI array\fP[\fI expression \fP] #\fR delete an array element\fP +exit\fR [ \fP\fIexpression \fP\fR]\fP #\fR exit immediately; status is \fP\fIexpression\fP +.EE +.DT +.PP +Statements are terminated by +semicolons, newlines or right braces. +An empty +.I expression-list +stands for +.BR $0 . +String constants are quoted \f5"\ "\fR, +with the usual C escapes recognized within. +Expressions take on string or numeric values as appropriate, +and are built using the operators +.B + - * / % ^ +(exponentiation), and concatenation (indicated by a blank). +The operators +.B +! ++ -- += -= *= /= %= ^= **= > >= < <= == != ?: +are also available in expressions. +Variables may be scalars, array elements +(denoted +.IB x [ i ] ) +or fields. +Variables are initialized to the null string. +Array subscripts may be any string, +not necessarily numeric; +this allows for a form of associative memory. +Multiple subscripts such as +.B [i,j,k] +are permitted; the constituents are concatenated, +separated by the value of +.BR SUBSEP . +.PP +The +.B print +statement prints its arguments on the standard output +(or on a file if +.BI > file +or +.BI >> file +is present or on a pipe if +.BI | cmd +is present), separated by the current output field separator, +and terminated by the output record separator. +.I file +and +.I cmd +may be literal names or parenthesized expressions; +identical string values in different statements denote +the same open file. +The +.B printf +statement formats its expression list according to the format +(see +.IR printf (3)). +The built-in function +.BI close( expr ) +closes the file or pipe +.IR expr . +.PP +The customary functions +.BR exp , +.BR log , +.BR sqrt , +.BR sin , +.BR cos , +.BR atan2 +are built in. +Other built-in functions: +.TF length +.TP +.B length +the length of its argument +taken as a string, +or of +.B $0 +if no argument. +.TP +.B rand +random number on (0,1) +.TP +.B srand +sets seed for +.B rand +.TP +.B int +truncates to an integer value +.TP +.BI substr( s , " m" , " n\fB) +the +.IR n -character +substring of +.I s +that begins at position +.IR m +counted from 1. +.TP +.BI index( s , " t" ) +the position in +.I s +where the string +.I t +occurs, or 0 if it does not. +.TP +.BI match( s , " r" ) +the position in +.I s +where the regular expression +.I r +occurs, or 0 if it does not. +The variables +.B RSTART +and +.B RLENGTH +are set to the position and length of the matched string. +.TP +.BI split( s , " a" , " fs\fB) +splits the string +.I s +into array elements +.IB a [1] , +.IB a [2] , +\&..., +.IB a [ n ] , +and returns +.IR n . +The separation is done with the regular expression +.I fs +or with the field separator +.B FS +if +.I fs +is not given. +.TP +.BI sub( r , " t" , " s\fB) +substitutes +.I t +for the first occurrence of the regular expression +.I r +in the string +.IR s . +If +.I s +is not given, +.B $0 +is used. +.TP +.B gsub +same as +.B sub +except that all occurrences of the regular expression +are replaced; +.B sub +and +.B gsub +return the number of replacements. +.TP +.BI sprintf( fmt , " expr" , " ...\fB ) +the string resulting from formatting +.I expr ... +according to the +.IR printf (3) +format +.I fmt +.TP +.BI system( cmd ) +executes +.I cmd +and returns its exit status +.PD +.PP +The ``function'' +.B getline +sets +.B $0 to +the next input record from the current input file; +.B getline +.BI < file +sets +.B $0 +to the next record from +.IR file . +.B getline +.I x +sets variable +.I x +instead. +Finally, +.IB cmd " | getline +pipes the output of +.I cmd +into +.BR getline ; +each call of +.B getline +returns the next line of output from +.IR cmd . +In all cases, +.B getline +returns 1 for a successful input, +0 for end of file, and \-1 for an error. +.PP +Patterns are arbitrary Boolean combinations +(with +.BR "! || &&" ) +of regular expressions and +relational expressions. +Regular expressions are as in +.IR egrep ; +see +.IR grep (1). +Isolated regular expressions +in a pattern apply to the entire line. +Regular expressions may also occur in +relational expressions, using the operators +.BR ~ +and +.BR !~ . +.BI / re / +is a constant regular expression; +any string (constant or variable) may be used +as a regular expression, except in the position of an isolated regular expression +in a pattern. +.PP +A pattern may consist of two patterns separated by a comma; +in this case, the action is performed for all lines +from an occurrence of the first pattern +though an occurrence of the second. +.PP +A relational expression is one of the following: +.IP +.I expression matchop regular-expression +.br +.I expression relop expression +.br +.I expression in array-name +.br +.I (expr,expr,...) in array-name +.PP +where a relop is any of the six relational operators in C, +and a matchop is either +.B ~ +(matches) +or +.B !~ +(does not match). +A conditional is an arithmetic expression, +a relational expression, +or a Boolean combination +of these. +.PP +The special patterns +.B BEGIN +and +.B END +may be used to capture control before the first input line is read +and after the last. +.B BEGIN +and +.B END +do not combine with other patterns. +.PP +Variable names with special meanings: +.TF SUBSEP +.TP +.B FS +regular expression used to separate fields; also settable +by option +.BI -F fs. +.TP +.BR NF +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 +.TP +.B RS +input record separator (default newline) +.TP +.B OFS +output field separator (default blank) +.TP +.B ORS +output record separator (default newline) +.TP +.B OFMT +output format for numbers (default +.BR "%.6g" ) +.TP +.B SUBSEP +separates multiple subscripts (default 034) +.TP +.B ARGC +argument count, assignable +.TP +.B ARGV +argument array, assignable; +non-null members are taken as filenames +.PD +.PP +Functions may be defined (at the position of a pattern-action statement) thus: +.IP +.L +function foo(a, b, c) { ...; return x } +.PP +Parameters are passed by value if scalar and by reference if array name; +functions may be called recursively. +Parameters are local to the function; all other variables are global. +.SH EXAMPLES +.TP +.L +length > 72 +Print lines longer than 72 characters. +.TP +.L +{ print $2, $1 } +Print first two fields in opposite order. +.PP +.EX +BEGIN { FS = ",[ \et]*|[ \et]+" } + { print $2, $1 } +.EE +.ns +.IP +Same, with input fields separated by comma and/or blanks and tabs. +.PP +.EX + { s += $1 } +END { print "sum is", s, " average is", s/NR } +.EE +.ns +.IP +Add up first column, print sum and average. +.TP +.L +/start/, /stop/ +Print all lines between start/stop pairs. +.PP +.EX +BEGIN { # Simulate echo(1) + for (i = 1; i < ARGC; i++) printf "%s ", ARGV[i] + printf "\en" + exit } +.EE +.SH SEE ALSO +.IR lex (1), +.IR sed (1) +.br +A. V. Aho, B. W. Kernighan, P. J. Weinberger, +.I +Awk \- a Pattern Scanning and Processing Language (Programmer'sManual), +CSTR 118, 1985 +.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; +to force it to be treated as a string concatenate +\f5""\fP to it. +.br +The scope rules for variables in functions are a botch. +.br +.L -S +and +.L -R +are flaky. |