Annotation of src/usr.bin/awk/awk.1, Revision 1.36
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1.36 ! deraadt 26: .Dd $Mdocdate: August 8 2010 $
1.7 aaron 27: .Dt AWK 1
28: .Os
29: .Sh NAME
30: .Nm awk
31: .Nd pattern-directed scanning and processing language
32: .Sh SYNOPSIS
33: .Nm awk
1.16 jmc 34: .Op Fl safe
35: .Op Fl V
36: .Op Fl d Ns Op Ar n
1.7 aaron 37: .Op Fl F Ar fs
1.16 jmc 38: .Oo Fl v Ar var Ns =
39: .Ns Ar value Oc
1.18 jmc 40: .Op Ar prog | Fl f Ar progfile
1.7 aaron 41: .Ar
42: .Sh DESCRIPTION
43: .Nm
1.1 tholo 44: scans each input
1.7 aaron 45: .Ar file
1.1 tholo 46: for lines that match any of a set of patterns specified literally in
1.7 aaron 47: .Ar prog
1.16 jmc 48: or in one or more files specified as
1.7 aaron 49: .Fl f Ar progfile .
1.16 jmc 50: With each pattern there can be an associated action that will be performed
1.1 tholo 51: when a line of a
1.7 aaron 52: .Ar file
1.1 tholo 53: matches the pattern.
54: Each line is matched against the
55: pattern portion of every pattern-action statement;
56: the associated action is performed for each matched pattern.
1.6 aaron 57: The file name
1.16 jmc 58: .Sq -
1.1 tholo 59: means the standard input.
60: Any
1.7 aaron 61: .Ar file
1.1 tholo 62: of the form
1.16 jmc 63: .Ar var Ns = Ns Ar value
1.1 tholo 64: is treated as an assignment, not a filename,
65: and is executed at the time it would have been opened if it were a filename.
1.16 jmc 66: .Pp
67: The options are as follows:
1.20 jmc 68: .Bl -tag -width "-safe "
1.16 jmc 69: .It Fl d Ns Op Ar n
70: Debug mode.
71: Set debug level to
72: .Ar n ,
73: or 1 if
74: .Ar n
75: is not specified.
76: A value greater than 1 causes
77: .Nm
78: to dump core on fatal errors.
79: .It Fl F Ar fs
80: Define the input field separator to be the regular expression
1.7 aaron 81: .Ar fs .
1.25 jmc 82: .It Fl f Ar progfile
1.16 jmc 83: Read program code from the specified file
1.25 jmc 84: .Ar progfile
1.16 jmc 85: instead of from the command line.
86: .It Fl safe
87: Disable file output
1.17 jmc 88: .Pf ( Ic print No > ,
89: .Ic print No >> ) ,
1.7 aaron 90: process creation
91: .Po
1.17 jmc 92: .Ar cmd | Ic getline ,
93: .Ic print No \&| ,
94: .Ic system
1.7 aaron 95: .Pc
96: and access to the environment
1.17 jmc 97: .Pf ( Va ENVIRON ;
1.18 jmc 98: see the section on variables below).
1.17 jmc 99: This is a first
1.16 jmc 100: .Pq and not very reliable
101: approximation to a
1.7 aaron 102: .Dq safe
103: version of
1.16 jmc 104: .Nm .
105: .It Fl V
106: Print the version number of
107: .Nm
108: to standard output and exit.
109: .It Fl v Ar var Ns = Ns Ar value
110: Assign
111: .Ar value
112: to variable
113: .Ar var
114: before
115: .Ar prog
116: is executed;
117: any number of
118: .Fl v
119: options may be present.
120: .El
1.7 aaron 121: .Pp
1.18 jmc 122: The input is normally made up of input lines
123: .Pq records
124: separated by newlines, or by the value of
125: .Va RS .
126: If
127: .Va RS
128: is null, then any number of blank lines are used as the record separator,
129: and newlines are used as field separators
130: (in addition to the value of
131: .Va FS ) .
132: This is convenient when working with multi-line records.
133: .Pp
1.7 aaron 134: An input line is normally made up of fields separated by whitespace,
1.18 jmc 135: or by the regular expression
1.7 aaron 136: .Va FS .
1.1 tholo 137: The fields are denoted
1.7 aaron 138: .Va $1 , $2 , ... ,
139: while
140: .Va $0
1.1 tholo 141: refers to the entire line.
142: If
1.7 aaron 143: .Va FS
1.1 tholo 144: is null, the input line is split into one field per character.
1.7 aaron 145: .Pp
1.18 jmc 146: Normally, any number of blanks separate fields.
147: In order to set the field separator to a single blank, use the
148: .Fl F
149: option with a value of
150: .Sq [\ \&] .
151: If a field separator of
152: .Sq t
153: is specified,
154: .Nm
155: treats it as if
156: .Sq \et
157: had been specified and uses
158: .Aq TAB
159: as the field separator.
160: In order to use a literal
161: .Sq t
162: as the field separator, use the
163: .Fl F
164: option with a value of
165: .Sq [t] .
166: .Pp
1.1 tholo 167: A pattern-action statement has the form
1.7 aaron 168: .Pp
169: .D1 Ar pattern Ic \&{ Ar action Ic \&}
170: .Pp
1.6 aaron 171: A missing
1.7 aaron 172: .Ic \&{ Ar action Ic \&}
1.1 tholo 173: means print the line;
174: a missing pattern always matches.
175: Pattern-action statements are separated by newlines or semicolons.
1.7 aaron 176: .Pp
1.18 jmc 177: Newlines are permitted after a terminating statement or following a comma
178: .Pq Sq ,\& ,
179: an open brace
180: .Pq Sq { ,
181: a logical AND
182: .Pq Sq && ,
183: a logical OR
184: .Pq Sq || ,
185: after the
186: .Sq do
187: or
188: .Sq else
189: keywords,
190: or after the closing parenthesis of an
191: .Sq if ,
192: .Sq for ,
193: or
194: .Sq while
195: statement.
196: Additionally, a backslash
197: .Pq Sq \e
198: can be used to escape a newline between tokens.
199: .Pp
1.1 tholo 200: An action is a sequence of statements.
201: A statement can be one of the following:
1.35 jmc 202: .Pp
203: .Bl -tag -width Ds -offset indent -compact
204: .It Xo Ic if ( Ar expression ) Ar statement
1.7 aaron 205: .Op Ic else Ar statement
206: .Xc
1.35 jmc 207: .It Ic while ( Ar expression ) Ar statement
208: .It Xo Ic for
209: .No ( Ar expression ; expression ; expression ) statement
210: .Xc
211: .It Xo Ic for
212: .No ( Ar var Ic in Ar array ) statement
213: .Xc
214: .It Xo Ic do
215: .Ar statement Ic while ( Ar expression )
216: .Xc
217: .It Ic break
218: .It Ic continue
219: .It Xo Ic {
220: .Op Ar statement ...
221: .Ic }
222: .Xc
223: .It Xo Ar expression
224: .No # commonly
225: .Ar var No = Ar expression
1.7 aaron 226: .Xc
1.35 jmc 227: .It Xo Ic print
1.7 aaron 228: .Op Ar expression-list
1.17 jmc 229: .Op > Ns Ar expression
1.7 aaron 230: .Xc
1.35 jmc 231: .It Xo Ic printf Ar format
1.7 aaron 232: .Op Ar ... , expression-list
1.17 jmc 233: .Op > Ns Ar expression
1.7 aaron 234: .Xc
1.35 jmc 235: .It Ic return Op Ar expression
236: .It Xo Ic next
237: .No # skip remaining patterns on this input line
238: .Xc
239: .It Xo Ic nextfile
240: .No # skip rest of this file, open next, start at top
241: .Xc
242: .It Xo Ic delete
243: .Sm off
244: .Ar array Ic \&[ Ar expression Ic \&]
245: .Sm on
246: .No # delete an array element
1.7 aaron 247: .Xc
1.35 jmc 248: .It Xo Ic delete Ar array
249: .No # delete all elements of array
1.7 aaron 250: .Xc
1.35 jmc 251: .It Xo Ic exit
1.7 aaron 252: .Op Ar expression
1.35 jmc 253: .No # exit immediately; status is Ar expression
1.7 aaron 254: .Xc
1.35 jmc 255: .El
1.7 aaron 256: .Pp
1.1 tholo 257: Statements are terminated by
258: semicolons, newlines or right braces.
259: An empty
1.7 aaron 260: .Ar expression-list
1.1 tholo 261: stands for
1.7 aaron 262: .Ar $0 .
263: String constants are quoted
264: .Li \&"" ,
1.20 jmc 265: with the usual C escapes recognized within
266: (see
267: .Xr printf 1
268: for a complete list of these).
1.1 tholo 269: Expressions take on string or numeric values as appropriate,
270: and are built using the operators
1.7 aaron 271: .Ic + \- * / % ^
1.20 jmc 272: .Pq exponentiation ,
273: and concatenation
274: .Pq indicated by whitespace .
1.1 tholo 275: The operators
1.16 jmc 276: .Ic \&! ++ \-\- += \-= *= /= %= ^=
277: .Ic > >= < <= == != ?:
1.1 tholo 278: are also available in expressions.
279: Variables may be scalars, array elements
280: (denoted
1.7 aaron 281: .Li x[i] )
1.1 tholo 282: or fields.
283: Variables are initialized to the null string.
284: Array subscripts may be any string,
285: not necessarily numeric;
286: this allows for a form of associative memory.
287: Multiple subscripts such as
1.7 aaron 288: .Li [i,j,k]
1.1 tholo 289: are permitted; the constituents are concatenated,
290: separated by the value of
1.17 jmc 291: .Va SUBSEP
1.31 deraadt 292: .Pq see the section on variables below .
1.7 aaron 293: .Pp
1.1 tholo 294: The
1.7 aaron 295: .Ic print
1.1 tholo 296: statement prints its arguments on the standard output
297: (or on a file if
1.17 jmc 298: .Pf > Ns Ar file
1.1 tholo 299: or
1.17 jmc 300: .Pf >> Ns Ar file
1.1 tholo 301: is present or on a pipe if
1.17 jmc 302: .Pf |\ \& Ar cmd
1.1 tholo 303: is present), separated by the current output field separator,
304: and terminated by the output record separator.
1.7 aaron 305: .Ar file
1.1 tholo 306: and
1.7 aaron 307: .Ar cmd
1.1 tholo 308: may be literal names or parenthesized expressions;
309: identical string values in different statements denote
310: the same open file.
311: The
1.7 aaron 312: .Ic printf
1.1 tholo 313: statement formats its expression list according to the format
314: (see
1.28 jmc 315: .Xr printf 1 ) .
1.18 jmc 316: .Pp
317: Patterns are arbitrary Boolean combinations
318: (with
319: .Ic "\&! || &&" )
320: of regular expressions and
321: relational expressions.
1.22 jmc 322: .Nm
323: supports extended regular expressions
324: .Pq EREs .
325: See
326: .Xr re_format 7
327: for more information on regular expressions.
1.18 jmc 328: Isolated regular expressions
329: in a pattern apply to the entire line.
330: Regular expressions may also occur in
331: relational expressions, using the operators
332: .Ic ~
333: and
334: .Ic !~ .
335: .Pf / Ns Ar re Ns /
336: is a constant regular expression;
337: any string (constant or variable) may be used
338: as a regular expression, except in the position of an isolated regular expression
339: in a pattern.
340: .Pp
341: A pattern may consist of two patterns separated by a comma;
342: in this case, the action is performed for all lines
343: from an occurrence of the first pattern
344: through an occurrence of the second.
345: .Pp
346: A relational expression is one of the following:
1.35 jmc 347: .Pp
348: .Bl -tag -width Ds -offset indent -compact
349: .It Ar expression matchop regular-expression
350: .It Ar expression relop expression
351: .It Ar expression Ic in Ar array-name
352: .It Xo Ic \&( Ns
1.18 jmc 353: .Ar expr , expr , \&... Ns Ic \&) in
1.35 jmc 354: .Ar array-name
1.18 jmc 355: .Xc
1.35 jmc 356: .El
1.18 jmc 357: .Pp
358: where a
359: .Ar relop
360: is any of the six relational operators in C, and a
361: .Ar matchop
362: is either
363: .Ic ~
364: (matches)
365: or
366: .Ic !~
367: (does not match).
368: A conditional is an arithmetic expression,
369: a relational expression,
370: or a Boolean combination
371: of these.
372: .Pp
373: The special patterns
374: .Ic BEGIN
375: and
376: .Ic END
377: may be used to capture control before the first input line is read
378: and after the last.
379: .Ic BEGIN
380: and
381: .Ic END
382: do not combine with other patterns.
383: .Pp
384: Variable names with special meanings:
385: .Pp
1.20 jmc 386: .Bl -tag -width "FILENAME " -compact
1.18 jmc 387: .It Va ARGC
388: Argument count, assignable.
389: .It Va ARGV
390: Argument array, assignable;
391: non-null members are taken as filenames.
392: .It Va CONVFMT
393: Conversion format when converting numbers
394: (default
395: .Qq Li %.6g ) .
396: .It Va ENVIRON
397: Array of environment variables; subscripts are names.
398: .It Va FILENAME
399: The name of the current input file.
400: .It Va FNR
401: Ordinal number of the current record in the current file.
402: .It Va FS
403: Regular expression used to separate fields; also settable
404: by option
405: .Fl F Ar fs .
406: .It Va NF
407: Number of fields in the current record.
408: .Va $NF
409: can be used to obtain the value of the last field in the current record.
410: .It Va NR
411: Ordinal number of the current record.
412: .It Va OFMT
413: Output format for numbers (default
414: .Qq Li %.6g ) .
415: .It Va OFS
416: Output field separator (default blank).
417: .It Va ORS
418: Output record separator (default newline).
419: .It Va RLENGTH
420: The length of the string matched by the
421: .Fn match
422: function.
423: .It Va RS
424: Input record separator (default newline).
425: .It Va RSTART
426: The starting position of the string matched by the
427: .Fn match
428: function.
429: .It Va SUBSEP
430: Separates multiple subscripts (default 034).
431: .El
1.17 jmc 432: .Sh FUNCTIONS
433: The awk language has a variety of built-in functions:
1.30 jmc 434: arithmetic, string, input/output, general, and bit-operation.
435: .Pp
436: Functions may be defined (at the position of a pattern-action statement)
437: thusly:
438: .Pp
439: .Dl function foo(a, b, c) { ...; return x }
440: .Pp
441: Parameters are passed by value if scalar, and by reference if array name;
442: functions may be called recursively.
443: Parameters are local to the function; all other variables are global.
444: Thus local variables may be created by providing excess parameters in
445: the function definition.
1.17 jmc 446: .Ss Arithmetic Functions
447: .Bl -tag -width "atan2(y, x)"
448: .It Fn atan2 y x
449: Return the arctangent of
450: .Fa y Ns / Ns Fa x
451: in radians.
452: .It Fn cos x
453: Return the cosine of
454: .Fa x ,
455: where
456: .Fa x
457: is in radians.
458: .It Fn exp x
459: Return the exponential of
460: .Fa x .
461: .It Fn int x
462: Return
463: .Fa x
464: truncated to an integer value.
465: .It Fn log x
466: Return the natural logarithm of
467: .Fa x .
1.7 aaron 468: .It Fn rand
1.17 jmc 469: Return a random number,
470: .Fa n ,
471: such that
472: .Sm off
473: .Pf 0 \*(Le Fa n No \*(Lt 1 .
474: .Sm on
475: .It Fn sin x
476: Return the sine of
477: .Fa x ,
478: where
479: .Fa x
480: is in radians.
481: .It Fn sqrt x
482: Return the square root of
483: .Fa x .
484: .It Fn srand expr
1.16 jmc 485: Sets seed for
1.7 aaron 486: .Fn rand
1.17 jmc 487: to
488: .Fa expr
1.1 tholo 489: and returns the previous seed.
1.17 jmc 490: If
491: .Fa expr
492: is omitted, the time of day is used instead.
493: .El
494: .Ss String Functions
495: .Bl -tag -width "split(s, a, fs)"
496: .It Fn gsub r t s
497: The same as
498: .Fn sub
499: except that all occurrences of the regular expression are replaced.
500: .Fn gsub
501: returns the number of replacements.
1.7 aaron 502: .It Fn index s t
1.16 jmc 503: The position in
1.7 aaron 504: .Fa s
1.1 tholo 505: where the string
1.7 aaron 506: .Fa t
1.1 tholo 507: occurs, or 0 if it does not.
1.17 jmc 508: .It Fn length s
509: The length of
510: .Fa s
511: taken as a string,
512: or of
513: .Va $0
514: if no argument is given.
1.7 aaron 515: .It Fn match s r
1.16 jmc 516: The position in
1.7 aaron 517: .Fa s
1.1 tholo 518: where the regular expression
1.7 aaron 519: .Fa r
1.1 tholo 520: occurs, or 0 if it does not.
1.17 jmc 521: The variable
1.7 aaron 522: .Va RSTART
1.17 jmc 523: is set to the starting position of the matched string
524: .Pq which is the same as the returned value
525: or zero if no match is found.
526: The variable
1.7 aaron 527: .Va RLENGTH
1.17 jmc 528: is set to the length of the matched string,
529: or \-1 if no match is found.
1.7 aaron 530: .It Fn split s a fs
1.16 jmc 531: Splits the string
1.7 aaron 532: .Fa s
1.1 tholo 533: into array elements
1.7 aaron 534: .Va a[1] , a[2] , ... , a[n]
1.1 tholo 535: and returns
1.7 aaron 536: .Va n .
1.1 tholo 537: The separation is done with the regular expression
1.7 aaron 538: .Ar fs
1.1 tholo 539: or with the field separator
1.7 aaron 540: .Va FS
1.1 tholo 541: if
1.7 aaron 542: .Ar fs
1.1 tholo 543: is not given.
544: An empty string as field separator splits the string
545: into one array element per character.
1.17 jmc 546: .It Fn sprintf fmt expr ...
547: The string resulting from formatting
548: .Fa expr , ...
549: according to the
1.28 jmc 550: .Xr printf 1
1.17 jmc 551: format
552: .Fa fmt .
1.7 aaron 553: .It Fn sub r t s
1.16 jmc 554: Substitutes
1.7 aaron 555: .Fa t
1.1 tholo 556: for the first occurrence of the regular expression
1.7 aaron 557: .Fa r
1.1 tholo 558: in the string
1.7 aaron 559: .Fa s .
1.1 tholo 560: If
1.7 aaron 561: .Fa s
1.1 tholo 562: is not given,
1.7 aaron 563: .Va $0
1.1 tholo 564: is used.
1.17 jmc 565: An ampersand
566: .Pq Sq &
567: in
568: .Fa t
569: is replaced in string
570: .Fa s
571: with regular expression
572: .Fa r .
573: A literal ampersand can be specified by preceding it with two backslashes
574: .Pq Sq \e\e .
575: A literal backslash can be specified by preceding it with another backslash
576: .Pq Sq \e\e .
1.7 aaron 577: .Fn sub
1.17 jmc 578: returns the number of replacements.
579: .It Fn substr s m n
580: Return at most the
581: .Fa n Ns -character
582: substring of
583: .Fa s
584: that begins at position
585: .Fa m
586: counted from 1.
587: If
588: .Fa n
589: is omitted, or if
590: .Fa n
591: specifies more characters than are left in the string,
592: the length of the substring is limited by the length of
593: .Fa s .
1.7 aaron 594: .It Fn tolower str
1.16 jmc 595: Returns a copy of
1.7 aaron 596: .Fa str
1.1 tholo 597: with all upper-case characters translated to their
598: corresponding lower-case equivalents.
1.7 aaron 599: .It Fn toupper str
1.16 jmc 600: Returns a copy of
1.7 aaron 601: .Fa str
1.1 tholo 602: with all lower-case characters translated to their
603: corresponding upper-case equivalents.
1.7 aaron 604: .El
1.17 jmc 605: .Ss Input/Output and General Functions
606: .Bl -tag -width "getline [var] < file"
607: .It Fn close expr
608: Closes the file or pipe
609: .Fa expr .
610: .Fa expr
611: should match the string that was used to open the file or pipe.
612: .It Ar cmd | Ic getline Op Va var
613: Read a record of input from a stream piped from the output of
614: .Ar cmd .
615: If
616: .Va var
617: is omitted, the variables
618: .Va $0
619: and
620: .Va NF
621: are set.
622: Otherwise
623: .Va var
624: is set.
625: If the stream is not open, it is opened.
626: As long as the stream remains open, subsequent calls
627: will read subsequent records from the stream.
628: The stream remains open until explicitly closed with a call to
629: .Fn close .
1.24 jmc 630: .Ic getline
631: returns 1 for a successful input, 0 for end of file, and \-1 for an error.
632: .It Fn fflush [expr]
633: Flushes any buffered output for the file, pipe
634: .Fa expr ,
635: or all open files or pipes if
636: .Fa expr
637: is omitted.
1.17 jmc 638: .Fa expr
639: should match the string that was used to open the file or pipe.
640: .It Ic getline
641: Sets
642: .Va $0
643: to the next input record from the current input file.
644: This form of
645: .Ic getline
646: sets the variables
647: .Va NF ,
648: .Va NR ,
649: and
650: .Va FNR .
1.7 aaron 651: .Ic getline
1.17 jmc 652: returns 1 for a successful input, 0 for end of file, and \-1 for an error.
653: .It Ic getline Va var
654: Sets
1.7 aaron 655: .Va $0
1.17 jmc 656: to variable
657: .Va var .
658: This form of
659: .Ic getline
660: sets the variables
661: .Va NR
662: and
663: .Va FNR .
664: .Ic getline
665: returns 1 for a successful input, 0 for end of file, and \-1 for an error.
666: .It Xo
667: .Ic getline Op Va var
668: .Pf \ \&< Ar file
669: .Xc
670: Sets
1.7 aaron 671: .Va $0
1.1 tholo 672: to the next record from
1.7 aaron 673: .Ar file .
1.17 jmc 674: If
675: .Va var
676: is omitted, the variables
677: .Va $0
678: and
679: .Va NF
680: are set.
681: Otherwise
682: .Va var
683: is set.
684: If
685: .Ar file
686: is not open, it is opened.
687: As long as the stream remains open, subsequent calls will read subsequent
688: records from
689: .Ar file .
690: .Ar file
691: remains open until explicitly closed with a call to
692: .Fn close .
693: .It Fn system cmd
694: Executes
695: .Fa cmd
696: and returns its exit status.
697: .El
1.30 jmc 698: .Ss Bit-Operation Functions
1.29 pyr 699: .Bl -tag -width "lshift(a, b)"
700: .It Fn compl x
701: Returns the bitwise complement of integer argument x.
702: .It Fn and x y
1.30 jmc 703: Performs a bitwise AND on integer arguments x and y.
1.29 pyr 704: .It Fn or x y
1.30 jmc 705: Performs a bitwise OR on integer arguments x and y.
1.29 pyr 706: .It Fn xor x y
1.30 jmc 707: Performs a bitwise Exclusive-OR on integer arguments x and y.
1.29 pyr 708: .It Fn lshift x n
709: Returns x shifted by n bits to the left.
710: .It Fn rshift x n
711: Returns y shifted by n bits to the right.
712: .El
1.7 aaron 713: .Sh EXAMPLES
1.16 jmc 714: Print lines longer than 72 characters:
715: .Pp
1.7 aaron 716: .Dl length($0) > 72
1.16 jmc 717: .Pp
718: Print first two fields in opposite order:
1.7 aaron 719: .Pp
720: .Dl { print $2, $1 }
1.16 jmc 721: .Pp
722: Same, with input fields separated by comma and/or blanks and tabs:
1.7 aaron 723: .Bd -literal -offset indent
1.1 tholo 724: BEGIN { FS = ",[ \et]*|[ \et]+" }
725: { print $2, $1 }
1.7 aaron 726: .Ed
1.16 jmc 727: .Pp
728: Add up first column, print sum and average:
1.7 aaron 729: .Bd -literal -offset indent
730: { s += $1 }
731: END { print "sum is", s, " average is", s/NR }
732: .Ed
1.16 jmc 733: .Pp
734: Print all lines between start/stop pairs:
1.7 aaron 735: .Pp
736: .Dl /start/, /stop/
1.16 jmc 737: .Pp
738: Simulate echo(1):
1.7 aaron 739: .Bd -literal -offset indent
740: BEGIN { # Simulate echo(1)
741: for (i = 1; i < ARGC; i++) printf "%s ", ARGV[i]
742: printf "\en"
743: exit }
1.19 jmc 744: .Ed
745: .Pp
746: Print an error message to standard error:
747: .Bd -literal -offset indent
748: { print "error!" > "/dev/stderr" }
1.7 aaron 749: .Ed
750: .Sh SEE ALSO
751: .Xr lex 1 ,
1.20 jmc 752: .Xr printf 1 ,
1.16 jmc 753: .Xr sed 1 ,
1.23 jmc 754: .Xr re_format 7 ,
755: .Xr script 7
1.7 aaron 756: .Rs
757: .%A A. V. Aho
758: .%A B. W. Kernighan
759: .%A P. J. Weinberger
760: .%T The AWK Programming Language
761: .%I Addison-Wesley
762: .%D 1988
763: .%O ISBN 0-201-07981-X
764: .Re
1.26 jmc 765: .Sh STANDARDS
766: The
767: .Nm
768: utility is compliant with the
1.33 jmc 769: .St -p1003.1-2008
1.26 jmc 770: specification.
771: .Pp
772: The flags
773: .Op Fl \&dV
774: and
775: .Op Fl safe ,
1.30 jmc 776: as well as the commands
777: .Cm fflush , compl , and , or ,
778: .Cm xor , lshift , rshift ,
1.26 jmc 779: are extensions to that specification.
1.32 jmc 780: .Pp
781: .Nm
782: does not support {n,m} pattern matching.
1.8 aaron 783: .Sh HISTORY
1.13 millert 784: An
1.8 aaron 785: .Nm
1.13 millert 786: utility appeared in
787: .At v7 .
1.7 aaron 788: .Sh BUGS
1.1 tholo 789: There are no explicit conversions between numbers and strings.
790: To force an expression to be treated as a number add 0 to it;
791: to force it to be treated as a string concatenate
1.7 aaron 792: .Li \&""
793: to it.
794: .Pp
1.1 tholo 795: The scope rules for variables in functions are a botch;
796: the syntax is worse.
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