AwkChannelWiki: Search for: "if"

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AA-awk-history
http://awk.freeshell.org/AA-awk-history\\ a concise history of awk and some of its forks\\ {{{ common . . .       http://lief.if.ufrgs.br/pub/linguagens/awk.pdf\\ [2] http://www.cs.bell-labs.com/cm/cs/awkbook/index.html\\ . . .
2K - last updated 2013-10-26 02:28 UTC by g0ph3r

action
== Default action == If a [[rule]] does not include an [[action]], then the default action is used. . . .
1K - last updated 2011-05-09 22:08 UTC by markhobley

Adler32Checksum
As documented in the [[http://en.wikipedia.org/wiki/Adler-32 | Adler-32 Wikipedia article]]. {{{ awk . . . adler32(str, a,b,len,i,j,MOD_ADLER,MAX_BLOCK) { if (!(sprintf("%c", int(rand()*256)) in ord)) for (i=0; . . . for # the presence of an existing 'ord' array. If we query for some # random character and it's not . . . calling functions to skip the init # process if they are smart, but that would then force this code . . . with at least 53 bits of precision, but # if we use these names and these values we make it easy . . .
4K - last updated 2008-12-31 12:05 UTC by pgas

AllAboutGetline
//Editor's notes: The article was originally posted on the comp.lang.awk newsgroup, and can still be . . . about getline usage, also reflects a specific point of view about it (that of the author), so . . . says: "The getline command is used in several different ways and should not be used by beginners. . . . gawk also populates the ERRNO builtin variable if getline fails. Although calling getline is very . . . rarely the right approach (see below), if you need to do it the safest ways to invoke getline . . .
16K - last updated 2009-02-15 22:14 UTC by waldner

awk-glossary
concise glossary of the essential awk  -  Last edited 2014-08-04 02:26 UTC\\ Contents: . . .      http://lief.if.ufrgs.br/pub/linguagens/awk.pdf\\ nawk:   . . .
5K - last updated 2014-08-04 03:23 UTC by y0tta

awk1page
an awk program is a series of //pattern { actions }// statements;\\ ie if the input line matchs pattern . . .
2K - last updated 2012-03-18 22:22 UTC by g0pher

awk Lucent Copyright notice
file FIXES from http://www.cs.princeton.edu/~bwk/btl.mirror/awk.zip ; version 20110810 {{{awk /***** . . . All Rights Reserved Permission to use, copy, modify, and distribute this software and its documentation . . . to distribution of the software without specific, written prior permission. LUCENT DISCLAIMS ALL . . .
2K - last updated 2012-08-26 11:45 UTC by g0ph3r

awk nawk oawk
in 1977 there was awk.\\ this page attempts to explain the history of awk.\\ the 1978 7th Edition awk(1) . . . = '%s'\n"; for(varname in SYMTAB) \ if ((varname != "ENVIRON") && (varname != "ARGV") . . .
2K - last updated 2012-03-18 23:21 UTC by g0pher

awka
Awka is comprised of an awk-to-C translator and a library the C code is linked against, to produce executables . . . clarification]] . . .
2K - last updated 2012-01-14 18:36 UTC by lewellyn

AwkDc
This is an awk implementation of the [http://www.gnu.org/software/bc/manual/dc-1.05/html_mono/dc.html|dc] . . . return stk[stk[SP]--] } # }}} ----- # TYPE VERIFICATION FUNCTIONS {{{ ----- function _dc_isnum(val) . . . tos1, i) { showop("xprint") tos1 = _dc_pop(stk) if (_dc_isstr(tos1)) { printf tos1 } else if (_dc_isnum(tos1)) . . . dc # handles the case. # FIXME: add a type-verification function to check # for integer values? This . . . tos1 = _dc_pop(stk) tos2 = _dc_pop(stk) if (_dc_isnum(tos1) && _dc_isnum(tos2)) { _dc_put(stk, . . .
12K - last updated 2008-07-17 14:47 UTC by gnomon

AwkFeatureComparison
This page lists which awk implementations support which features. Additions and corrections are very . . . supports |=Feature|=Test code # expected result if feature is supported| |={m,n} repetition in RE|{{{echo . . .
4K - last updated 2015-04-27 13:23 UTC by pgas

AwkGuide
** Work in Progress ** {{{ import from Mark Hobley's wiki }}} <toc> ---- == Overview * [[Overview]] . . . * [[control structure]]s * [[conversion qualifier]]s * [[conversion specifier]]s * [[datatype]]s . . . * [[hash]] symbol * [[here document]]s * [[identifier]]s * [[if]] conditional constructs * [[include]] . . . * [[locale]] * [[loop]]s * [[loop modifier]]s * [[limitation]]s * [[loop]]s * [[main]] * . . . [[whitespace]] == Conversion of scripts to suit different awk versions * [[Converting gawk scripts to . . .
4K - last updated 2011-08-14 15:57 UTC by markhobley

AwkOnWindows
[[AwkOnWindows|This page]] lists available versions of awk for ms windows.\\ Example: //awk /foo/{print(NR,$0)} . . . //foo//\\ preceded by the line number.\\ If new to awk, start here [[HomePage|AwkChannelWiki]].\\ . . . If new to windows start here [[GettingStarted|GettingStarted]] . . . 88kB\\ newer version if bwk's awk95.exe 20100228 version 149kB\\ compiled . . .
2K - last updated 2010-10-24 09:39 UTC by g0pher

AwkOnWindowsHowto
AwkOnWindowsHowto\\ rough cut - needs edit {{{ 3) awk command line switches/usage from a win32 cmd.exe . . . values of variables for(varname in SYMTAB) \ if ((varname != "ENVIRON") && (varname != "ARGV") . . .
3K - last updated 2010-10-24 07:44 UTC by g0pher

AwkTips
<toc> ---- == Be idiomatic! In this paragraph, we give some hints on how to write more idiomatic . . . that match some pattern (a kind of awk-grep, if you like). A reasonable first shot is usually something . . . like {{{ awk '{if ($0 ~ /pattern/) print $0}' }}} That works, but . . . {print $0}' }}} Our next step in the perfect awk-ification of this program is to note that **/pattern/** . . . implicitly applies it to $0, and returns success if there is a match. Then we have: {{{ awk '/pattern/ . . .
31K - last updated 2009-03-24 16:54 UTC by waldner

AwkVsPerl
A valid question, since awk is a subset of perl (functionally, not necessarily syntactically); also, . . . almost no version of awk can do without great difficulty (if at all); if you need to do these things, . . . server in awk instead of using perl or even C, if the actual socket programming has to be written . . . to perl: * awk is simpler (especially important if deciding which to learn first) * awk syntax is far . . . more > power that comes at expense of sacrificing some of that simplicity. }}} . . .
2K - last updated 2011-01-22 05:33 UTC by steve

AwkVsPerlJapanese
A valid question, since awk is a subset of perl (functionally, not necessarily syntactically); also, . . . almost no version of awk can do without great difficulty (if at all); if you need to do these things, . . . server in awk instead of using perl or even C, if the actual socket programming has to be written . . . to perl: * awk is simpler (especially important if deciding which to learn first) * awk syntax is far . . . more > power that comes at expense of sacrificing some of that simplicity. }}} . . .
2K - last updated 2008-11-24 08:05 UTC by pgas

Backref2
The usual (and correct) answer for backreferences in awk (for example, the answer you can get on #awk . . . in awk". That is only partly true. If you need to //**match**// a pattern using a regular . . . well, you can't do that easily with awk. But if you are using backreferences during string substitution, . . .
2K - last updated 2009-03-26 20:24 UTC by waldner

Backreferences
The usual (and correct) answer for backreferences in awk (for example, the answer you can get on #awk . . . in awk". That is only partly true. If you need to //**match**// a pattern using a regular . . . well, you can't do that easily with awk. But if you are using backreferences during string substitution, . . . letter and following digit and insert "+" if letter is "a" or "c" $ echo 'a1-b2-c3-a5-s6-a7-f8-e9-a0' . . . unlike sub() and gsub(), returns the modified string without touching the original. Also note . . .
3K - last updated 2010-12-30 06:53 UTC by ppp089210039107.dsl.hol.gr

BackslashInRegexp
Because {{{"\\$"}}} is a string and {{{/\\$/}}} is not; in strings, some of the escape characters get . . . that look similar but behave totally differently: {{{ /$N|S$$E|W$/ => `(N' or `S)(E' . . . only }}} There is also confusion regarding different forms of special characters; POSIX requires . . .
2K - last updated 2008-11-26 12:27 UTC by pgas

BeforeAfterMatch
Problem: print the Nth record before or after a certain regular expression matches or, alternativley, . . . is that they use a single counter (c), so if matches are separated by less than N lines, then . . . NR in a' file }}} Use i=0 in the for definition if you want to include the matching record itself. . . . normal regex match as above can have problems if the pattern contains regular expression metacharacters, . . .
3K - last updated 2009-02-28 20:38 UTC by waldner

BEGIN
== Begin Blocks The [[awk]] programming language allows us to use **begin blocks** and **end blocks** . . . is no current record when a begin block is run. If multiple begin blocks are defined within a script, . . . that they are defined within the awk script. If the script contains only BEGIN rules and no other . . . after the BEGIN rules have been run. However, if an END rule exists, then the input is read, even . . . if there are no other rules in the program. This behaviour . . .
3K - last updated 2013-04-11 14:25 UTC by 92.40.253.171.threembb.co.uk

bitwise operator
Traditional [[awk]] implementations do not support bitwise operators. == Function Gawkisms == Bitwise . . . the following [[gawkism]]s: * [[and]] * [[lshift]] * [[or]] * [[rshift]] * [[xor]] . . .
1K - last updated 2011-03-07 19:55 UTC by markhobley

branch
A branch is a [[control structure]] that allow a particular section of code to be conditionally executed . . . keywords for defining branches, including: [[if]], [[else]] === Using logical operators === The . . .
1K - last updated 2011-04-17 06:37 UTC by markhobley

CAAN-or-caan
**caan:     the comprehensive awk archive network**\\     -or-\\ . . . **Intro:**\\ historical:   http://lief.if.ufrgs.br/pub/linguagens/awk.pdf\\     . . .
4K - last updated 2014-05-29 02:01 UTC by g0ph3r

case sensitivity
== Indentifier names == The [[awk]] interpreter is lettercase sensitive. This means that [[variable name]]s . . . that have different letter cases are distinct and separate from . . . each other: {{{ awk # The identifiers dog,Dog and DOG represent separate variables . . . sensitive, [[pattern]] matching will only occur if the lettercase of the text matches that used in . . .
1K - last updated 2011-06-25 05:14 UTC by pgas

CaseInsensitive
{{{}}}**Use tolower()** * portable * must be explicitly used for each comparison Instead of: {{{ awk . . . if (avar=="a" || avar=="A") { ... } }}} Use: {{{ awk . . . if (tolower(avar)=="a") { ... } }}} Or at the beginning . . .
1K - last updated 2008-11-26 12:39 UTC by pgas

CAWKLib
=CAWKLib CAWKlib is a library of functions for for awk intended to be used with preprocessors/wrappers . . . on a Web Framework to be written in AWK called Cliff's Awesome Web (application) Kit or CAWK ## The . . . character capitalized and the rest lowercase. If a second parameter is specified it is used as a . . . supplied string inside the new string of the specified length shc_test.awk: *shc_test() -- low level . . . shell command *file_isblock() -- returns 1 if file is a block device *file_ischar() -- returns . . .
5K - last updated 2015-01-29 10:14 UTC by 108-243-116-77.lightspeed.cicril.sbcglobal.net

Columnate
This script columnates the input file, so that columns line up like in the GNU column(1) command. Its . . . END, the lines are printed in columnated format. If your terminal is not too narrow, you'll get a handsome . . . line for (f=1; f<=NF; f++) { len = length($f) if (len>max[f]) max[f] = len # an array of maximum . . .
1K - last updated 2009-02-28 21:32 UTC by h-67-101-152-180.nycmny83.dynamic.covad.net

comp.lang.awk FAQ
This material of this faq originates from the comp.lang.awk FAQ that you can find there: * http://www.faqs.org/faqs/computer-lang/awk/faq/ . . . ---- == Is there an easy way to determine if you have oawk or nawk? <include "oawk or nawk"> . . .
8K - last updated 2009-03-04 12:42 UTC by pgas

comp.lang.awk FAQJapanese
This material of this faq originates from the comp.lang.awk FAQ that you can find there: * http://www.faqs.org/faqs/computer-lang/awk/faq/ . . . ---- == Is there an easy way to determine if you have oawk or nawk? <include "oawk or nawkJapanese"> . . .
4K - last updated 2008-11-24 09:01 UTC by pgas

comparative operator
The comparative operators are used to determine equality or inequality or otherwise make comparisons . . . lexical ordering: {{{ BEGIN { a="BALL" b="BELL" if (a == b) { print "The strings are equal" } if (a . . . != b) { print "The strings are not equal" } if (a > b) { print "The first string is lexically . . . after than the second" } if (a < b) { print "The first string is lexically . . . before than the second" } if (a >= b) { print "The first string is not lexically . . .
3K - last updated 2013-02-24 17:38 UTC by markhobley

ComparingTwoFiles
Sometimes it is useful to compare two files. To do this in awk, the trick is to load the data from the . . . on the records of file2 because of the next. If $1 is present in arr, ie in file1, the default action . . .
2K - last updated 2011-08-25 00:35 UTC by steve

concatenation
== The awk programming language does not have an explicit concatenation operator == The awk programming . . . concatenation of [[numeric]] values will occur if [[whitespace]] is used between them: {{{ awk # This . . . [[addition]], so unexpected results may occur, if numeric [[value]]s are represented this way within . . .
1K - last updated 2011-06-25 05:13 UTC by pgas

ContextGrep
The following snippets print matching lines with surrounding context lines, like GNU grep's **grep -A . . . after each match). {{{ awk $0 ~ Pattern { # if we found the pattern ... if (seen++ && NR>afterlineno+1) . . . # if we already found another block # and are outside . . . "Regex" as pattern): {{{ awk awk -v N=3 '/Regex/{if (seen++ && NR>a+1)print "--"; a = NR+N} . . . the file, but this slows down the process significantly. Here's a way of doing it (this time, the . . .
3K - last updated 2011-07-01 08:32 UTC by pgas

control structure
'''Control structures''' are constructs used to control the logic of a program based on a given condition. . . . being used as a conditional [[branch]]: {{{ awk if (guess == 6) { print "Wow! That was a lucky guess." . . . # we are within an if block here } }}} === _Loops_ The following example . . .
1K - last updated 2011-06-25 05:08 UTC by pgas

ConvertHexToFloatingPoint
This code uses [[gawkism|gawk specific features]], such as the [[http://www.gnu.org/manual/gawk/html_node/Strtonum-Function.html][strtonum]] . . . exponent=and(i3,0x7F) tmp=and(i2,0x80) tmp=rshift(tmp, 7) exponent=lshift(exponent, 1) exponent=or(exponent,tmp) . . . the fraction fraction=and(i2,0x7F) fraction=lshift(fraction,8) fraction=or(fraction,i1) fraction=lshift(fraction,8) . . . base 10 value decfrac=0 for(i=22;i>=0;i--) { if( and( fraction , lshift(0x01,i) )) decfrac = decfrac+2^(i-23) . . . } fval=(1+decfrac) * 2^(exponent-bias) if(sign) fval=fval*-1 return fval } BEGIN { } { print . . .
3K - last updated 2010-06-23 19:49 UTC by john b

CookBook
<toc> ---- Just started, the aim of this page is to collect small pieces of code that illustrate . . . specific problems. == Looping on all the fields(columns) . . . Edit this answer]] ---- == How to test if an array is empty <include "EmptyArray"> [[http://awk.freeshell.org/?action=edit;id=EmptyArray| . . .
1K - last updated 2009-04-14 09:03 UTC by 216.162.199.202

DeleteTrailingNewlines
Simple oneliner that deletes the trailing newlines of a file: {{{ sh awk '!NF{b=b "\n";next} {printf . . . file }}} Explanations: * !NF : "If the line is blank (ie NF==0), then accumulate the . . . newline in b, then skip the rest" * "If the line is not blank, print the accumulated newline, . . . newlines are stored in b, but never printed. If you want to keep one trailing newline, add one ;): . . .
1K - last updated 2008-12-31 12:07 UTC by pgas

division
== Quotient Division == The [[slash]] symbol can be used as the division [[operator]] to produce the . . . behaviour is to abort awk with a fatal error, if a division by zero is encountered. === mawk === . . . interpreter does not abort with a fatal error if a division by zero is encountered. Instead mawk . . .
2K - last updated 2011-03-20 07:07 UTC by markhobley

dollarint
A [[dollar]] sign and followed by an [[integer]] are used to refer to [[field]]s within the current [[record]]: . . . you would write fields[1] in awk you write $1 If you know C it behaves like the * on a pointer. == . . . a [[constant]]. === Using a variable name to specify the field number === It is possible to use to use . . . name]] after the [[dollar]] sign to specify the field number: {{{ awk { myfield = 4 print $myfield . . . number 4 } }}} === Using an expression to specify the field number === It is also possible to use . . .
3K - last updated 2011-06-25 05:28 UTC by pgas

EditInPlace
You cannot edit a file in place with awk. What you should do is direct your output to a temporary file, . . . and, if everything is fine, rename the temporary file: {{{ . . . && mv tmpfile.txt originalfile.txt }}} If you have special requirements, you can of course . . . behind the scenes and then rename it anyway). If you are brave and are happy at the idea of losing . . .
1K - last updated 2009-04-11 17:29 UTC by waldner

EmptyArray
You can test if an array is empty using this function: {{{ awk function empty(a, i) { for(i in a) return . . .
1K - last updated 2009-03-12 08:11 UTC by pgas

ENVIRON
Modern versions of new awk (gawk, mawk, Bell Labs awk, any POSIX awk) all provide an array named ENVIRON. . . . = '%s'\n", i, ENVIRON[i]) }}} What if my awk doesn't have ENVIRON[]? Short answer, get . . . but this is less pretty, and may be a problem if the values contain newlines: {{{ awk # test this . . .
1K - last updated 2008-11-19 13:13 UTC by pgas

ENVIRONJapanese
Modern versions of new awk (gawk, mawk, Bell Labs awk, any POSIX awk) all provide an array named ENVIRON. . . . = '%s'\n", i, ENVIRON[i]) }}} What if my awk doesn't have ENVIRON[]? Short answer, get . . . but this is less pretty, and may be a problem if the values contain newlines: {{{ awk # test this . . .
1K - last updated 2008-11-24 08:05 UTC by pgas

EnvVarGeneral
**Answer 1:** On Unix, use "alternate quoting", e.g. {{{ awk -F: '$1 ~ /'"$USER"'/ {print $5}' /etc/passwd . . . a description of -v: **Answer 2:** RTFM to see if and how your awk supports variable definitions on . . . {print $5}' /etc/passwd }}} **Answer 3** RTFM if your awk can access enviroment vars. Then perhaps . . . command argument in '...' across multiple lines if need be. Also note: /bin/csh requires a \ before . . .
3K - last updated 2011-07-05 09:31 UTC by pgas

ExitCode
Normally, the `exit' command exits with a value of zero. You can supply an optional numeric value to . . . command to make it exit with a value: {{{ awk if (whatever) exit 12; }}} If you have an END block, . . . END block, an `exit' command exits immediately; if you had previously supplied a value, that value . . . is used. But, if you give a new value to `exit' within the END block, . . . in the GNU Awk User's Guide (gawk.texi). If you have an END block you want to be able to skip . . .
1K - last updated 2008-11-26 12:30 UTC by pgas

field reference
== The field reference operator == The [[dollar]] symbol acts as a unary *field reference operator* and . . . number 123 }}} ==== Using a variable name to specify the field number ==== It is possible to use to . . . a [[variable name]] after the dollar sign to specify the field number: {{{ { myfield = 4 print $myfield . . . number 4 } }}} === Using an expression to specify the field number === It is also possible to use . . . an [[expression]] after the dollar sign to specify the field number. Note that [[parentheses]] are . . .
2K - last updated 2011-06-28 09:12 UTC by markhobley

FieldReference
$ is the "field reference" operator in AWK. It references the field in the current input record given . . . by the variable or constant. E.g. if you want to print the first field, the following . . . print i, $i; # print the field at $i, but only if it something other than the empty # string: if ($i . . .
1K - last updated 2009-01-03 01:51 UTC by fcr

FileAndBitJoinClone
== Problem Description This was difficult to hash out. Eventually the task was described as, "for each . . . double-checked. # # The output format will be different, of course, but this is a matter of messing . . . gU14Ku37htPTxLnbb1L9Os+M5ulnlfSL63S0TkfrTGed6aynk3U6Wee5Wqne . . . 1hgJzQc8IhSiFTwiFKIVPCIUohU8IpSiFTwilKIVyCGUohVUIZSiNfZK8wFV CIVoBVUIhWhtkQENCMghlKIVyCGUohXgIJSiNcCBUrQGOFCKjkuBQrQGOFCI . . . aUAD6VGI1iAZCtGKpyNCIVoDcyhE60B6FKIVzx6FUrQGIFGKVjwDEUrRGvS0 eEBIj1J0NC2FaA16ohCtQU8UohX0pBSiFfSkFKIV9KSUohX0pJSidXaINCCg . . .
7K - last updated 2009-03-08 16:26 UTC by waldner

FileExistence
The most portable way to test for the existence of a file is to simply try and read from the file. {{{ . . . awk function exists(file, dummy, ret) { ret=0; if ( (getline dummy < file) >=0 ) { # file exists . . . you can probably use the `test' utility {{{ awk if (system("test -r " file) == 0) # file is readable . . .
1K - last updated 2008-11-18 13:26 UTC by pgas

FileExistenceJapanese
The most portable way to test for the existence of a file is to simply try and read from the file. {{{ . . . awk function exists(file, dummy, ret) { ret=0; if ( (getline dummy < file) >=0 ) { # file exists . . . you can probably use the `test' utility {{{ awk if (system("test -r " file) == 0) # file is readable . . .
1K - last updated 2008-11-24 08:07 UTC by pgas

FindAllIndices
Sometimes it is useful to find the index of every occurrence of a given character in a string. Let's . . . every backslash character; # for each backslash, if the index + 1 of that backslash is in the list of . . . i, j) { for (i = 1; i <= length(str); i++) if (substr(str, i, 1) == chr) arr[++j] = i return j . . . (gsub() is a faster way of accomplishing this if that's all that is needed). The *arr* argument is . . . out so that it can be filled with indices of different characters by repeated invocation. The escaped-doublequote . . .
2K - last updated 2011-07-05 10:53 UTC by pgas

FindAllMatches
This bit of code will match all non-overlapping instances of a given pattern in a string and will store . . . the matches in the string in the start[] array; if you want to do so, you need to uncomment the relevant . . . code and modify the argument list to add the start[] array {{{ . . . arr, j, a, b) { j=0 # eaten = 0 # optional: used if start[] is needed a = RSTART; b = RLENGTH # to avoid . . . 0-length matches. TODO: handle anchored REs (eg, if RE is "^foo" and str is "foofoo", return only one . . .
2K - last updated 2009-03-24 09:46 UTC by waldner

FirstFile
you can tell if awk is parsing the first file given on the command line using FILENAME, thusly: {{{ awk . . . { replace[$1] = $0; } rulesfile != FILENAME \ { if ($1 in replace) print replace[$1]; else print; } . . .
1K - last updated 2008-11-18 13:34 UTC by pgas

FirstFileJapanese
you can tell if awk is parsing the first file given on the command line using FILENAME, thusly: {{{ awk . . . { replace[$1] = $0; } rulesfile != FILENAME \ { if ($1 in replace) print replace[$1]; else print; } . . .
1K - last updated 2008-11-24 08:09 UTC by pgas

FIXES
[[FIXES]]        revised:   . . . ENVIRON array contains environment: if shell variable V=thing,\\     ENVIRON["V"] . . . it would have been opened if it were a filename (p 63).\\ added some missing . . .     program if the program is on the commandline.\\     requires . . . the same changes for field-splitting if FS is "".\\ \\ added nextfile, as in gawk: causes . . .
6K - last updated 2014-01-15 23:17 UTC by g0ph3r

ForceNumeric
These are the canonical, work-in-all-versions snippets. There are many others, most longer, some shorter . . . two variables as numbers ONLY, use {{{ awk if (0+var1 == 0+var2) }}} To compare two variables . . . as non-numeric strings ONLY, use {{{ awk if ("" var1 == "" var2) }}} . . .
1K - last updated 2008-11-26 12:43 UTC by pgas

FormatFileSizes
From time to time people ask how to sort the output of {{{du -h}}}. This is not particularly easy, since . . . for (i=3;i>=0;--i) { if ( size > 1024 ^i) {printf "%.2f%s\t%s\n",(size . . .
1K - last updated 2008-11-29 05:22 UTC by gnomon

FS
= Field Separator = The [[special variable]] FS is a field separator that is used to determine how [[awk]] . . . }' }}} == Matching a single space delimiter == If you really want to use a single space delimiter, . . . }}} Note that the second awk command gives a different result, because the leading whitespace is . . . seem to treat t as just a normal letter ** {{{ If the -F command line switch is given a single letter . . . backslash escape characters can become lost. If the letter t should really be used as a field separator, . . .
5K - last updated 2013-02-19 21:45 UTC by markhobley

gawk
===gawk=== The [http://www.gnu.org/software/gawk/|GNU] version of awk. It features decent compatibility . . . the version of awk most people are familiar with if they come from the Linux side of the world. . . .
1K - last updated 2011-03-30 03:33 UTC by 87.83.232.221.broad.wh.hb.dynamic.163data.com.cn

gawkism
Gawkisms are non portable syntax components that do not work with some awk implementations. The use of . . . notation * [[IGNORECASE]] * [[LINT]] * [[lshift]] (bitwise function) * [[mktime]] function * [[nextfile]] . . . * [[RS]] can be a [[regular expression]] * [[rshift]] (bitwise function) * [[RT]] * [[strftime]] function . . .
2K - last updated 2011-05-19 22:29 UTC by markhobley

GeneralizedTextReplacement
Some times people need to recode in awk something they were previously doing with sed or another tool. . . . More specifically, one may need to emulate most of sed's features . . . we will discuss how to emulate sed with awk (specifically, the s/pattern/replacement/ command), establishing . . . all the occurrences, like sed 's/foo/bar/g). If you need to replace only the nth occurrence (where . . . command in sed), loop over them to modify each one as needed and store the replacements in . . .
6K - last updated 2009-03-26 20:38 UTC by waldner

Genius
http://awk.freeshell.org/Genius\\ Genius  People  - was looking for people that contributed . . . of theoretical computer science and artificial intelligence\\ http://en.wikipedia.org/wiki/Thomas_Watson,_Jr. . . . http://en.wikipedia.org/wiki/Clifford_A._Pickover    1957-\\ http://en.wikipedia.org/wiki/Eric_Cartman . . .
6K - last updated 2014-07-07 06:17 UTC by y0tta

GeoLocation
{{{ awk #!/bin/gawk -f function getcoord(string, a) { split(string, a, ":") gsub(/\"/, "", a[2]) return . . . = 0 in_body = 0 while (socket |& getline) { if (in_body) return $0 if (/^\r$/) in_body = 1 } } . . .
1K - last updated 2011-11-14 16:35 UTC by pgas

getline
The *getline* command can obtain input from any number of files and does not require a command line parameter . . . | getline}}} foobar | foobar === Failure === If a [[failure]] occurs during the [[getline]] operation, . . . function. In [[awk]], output to a specific file is achieved by using [[redirection]]. . . .
1K - last updated 2011-05-02 20:14 UTC by markhobley

Glossary
[[Glossary| Glossary]]\\ see also [[AwkOnWindows| AwkOnWindows]] and [[FIXES| FIXES]] and [[AwkOnWindowsHowto| . . . tab, and formfeed.' me: 'yes, i am an idiot' 'if it aint broke, i can break it' }}} . . .
2K - last updated 2010-10-24 08:14 UTC by g0pher

HomePage
This wiki is maintained by regulars from the **#awk** channel on **[[https://libera.chat/|irc.libera.chat]]** . . . are summarized at the bottom of the edit box. If you are afraid to break something, feel free to . . . play in the SandBox. If you feel you need more info see [[How to edit]]. . . . is small with a low traffic, and is not different from the other channels of this size on irc . . . ie: * Do not wait to see if someone is awake to ask your question, we will answer . . .
5K - last updated 2023-06-26 04:15 UTC by HappMacDonald

HomePageJapanese
Here is the Japanese page for [[HomePage]]. 英語のページは[[HomePage|こちら]]です。この wiki は **[[http://www.freenode.net|irc.freenode.net]]** . . . - The Single UNIX Specification (ここには awk のソースコードとして受け入れられている正確な文法を定義している素晴らしい章を含んでいます) . . .
5K - last updated 2008-10-19 07:34 UTC by hi saito

How do I report a bug in gawk
This is described in great detail in the gawk documentation. In brief: # Make sure what you've discovered . . . really a bug by checking the documentation and, if possible, comparing with nawk and mawk. # Cut down . . .
1K - last updated 2008-11-18 12:07 UTC by pgas

How do I report a bug in gawkJapanese
This is described in great detail in the gawk documentation. In brief: # Make sure what you've discovered . . . really a bug by checking the documentation and, if possible, comparing with nawk and mawk. # Cut down . . .
1K - last updated 2008-11-24 08:07 UTC by pgas

if
The if [[condition]]al construct allows a [[statement]] or [[block]] of code to be [[condition]]ally . . . within the [[condition]], only gets executed if the [[expression]] evaluates to a [[true]] value. . . . The if [[condition]] its simplest form is: == if (CONDITION) . . . STATEMENT == For example: {{{ if (guess == 6) print "Wow! That was a lucky guess." . . . }}} == There are no then or endif cocomponents == Note that the [[awk]] extraction . . .
2K - last updated 2011-09-11 21:43 UTC by 92.40.253.171.threembb.co.uk

include
The [[awk]] extraction and reporting language does not support the use of include files. However, it . . . awk -f one.awk -f two.awk }}} === _Functions in different source files will be visible_ The functions . . . defined in different source files will be visible from other scripts . . .
2K - last updated 2013-03-30 10:38 UTC by markhobley

index
== Usage == === index [ STRING, SUBSTRING ] === The index [[function]] is used to locate the first occurrence . . . of a [[substring]] within a [[string]]. If the [[substring]] cannot be found, then a value . . . sensitive]], so a [[match]] will only occur if the lettercase of the [[string]] matches that of . . .
1K - last updated 2011-06-09 20:36 UTC by markhobley

Inicio
Este wiki es mantenido por los usuarios del cenal **#awk** en **[[http://www.freenode.net|irc.freenode.net]]**. . . . == Conversiones de programas para funcionar en diferentes versiones de awk * [[ConvirtiendoProgramasEnGawkAlAwkTradicional]] . . . & Utilities Reference", The Single UNIX Specification (includes a nifty section defining the precise . . . with gawk", a relatively obscure but /very/ nifty document explaining how to make impressive use . . . to sniff] that their OS offers a proper /net entry in the . . .
7K - last updated 2009-02-12 23:31 UTC by fcr

input
The [[awk]] utility can take its input from [[standard input]] or from [[file]]s. If no input files are . . . specified at the command line, then [[awk]] will take its . . . from a particular file without the need to specify the filename as a command line parameter. == Special . . . file | [[FS]] | A control variable that specifies the input field separator | [[NF]] | An informative . . . processed | [[RS]] | A control variable that specifies the input record separator . . .
2K - last updated 2011-05-19 22:40 UTC by markhobley

iterative loop
An '''iterative loop''' repeatedly executes a set of instructions as the [iterator] steps through a series . . . before each iteration of the [loop], and if it evaluates to [true], the [loop] is executed. . . . If the test condition does not evaluate to [true], . . .
2K - last updated 2011-08-13 21:00 UTC by markhobley

jawk
===jawk=== An awk clone targeting the JVM. Can be found [http://jawk.sourceforge.net/|on its SourceForge . . . the overwhelmingly large set of Java libraries if desired (all on an explicit opt-in basis) and it . . .
1K - last updated 2011-03-30 03:30 UTC by 87.83.232.221.broad.wh.hb.dynamic.163data.com.cn

keyword
A keyword is a reserved word that has a special meaning to the [[awk]] interpreter. A keyword cannot . . . be used as an [[identifier]] name within an [[awk]] script. The following . . .
1K - last updated 2010-10-25 11:38 UTC by markhobley

LargestAccurateNumber
Most [[awk]] implementations use floating point double precision to represent every kind of numeric value. . . . is because the fraction field is interpreted differently in different circumstances. If **all** of . . . this means there's +0 and -0. Thanks, IEEE!) If the exponent field has **any** non-zero bits, it . . .
3K - last updated 2013-04-12 14:52 UTC by ttmrichter

LevenshteinEditDistance
The [http://en.wikipedia.org/wiki/Levenshtein_distance|Levenshtein edit distance] calculation is useful . . . the end of the string rather than the beginning. If experiments are run, the results will also appear . . . str2, l1, l2, tog, arr, i, j, a, b, c) { if (str1 == str2) { return 0 } else if (str1 == "" . . . || str2 == "") { return length(str1 str2) } else if (substr(str1, 1, 1) == substr(str2, 1, 1)) { a = . . . levdist(substr(str1, a), substr(str2, a)) } else if (substr(str1, l1=length(str1), 1) == substr(str2, . . .
6K - last updated 2010-04-16 10:19 UTC by pgas

libmawk
libmawk is a fork of [[mawk]], designed for embedding in C programs. Compare and contrast with [[awka]]. . . . manner - that is, the script will not block if the process can not provide new input * all these . . .
2K - last updated 2012-01-16 09:07 UTC by lewellyn

limitation
== Limitations of awk Some traditional versions of [[awk]] derived from [[Unix]] version 7, may not conform . . . input It is a requirement of [[posix]] that if a program contains only [[BEGIN]] actions, and contains . . .
1K - last updated 2009-04-20 15:50 UTC by Mark Hobley

LinksPage
<toc> ---- == websites dedicated to awk == * [[http://awk.info/|awk.info]] news and articles about . . . & Utilities Reference", The Single UNIX Specification (includes a nifty section defining the precise . . . with gawk", a relatively obscure but /very/ nifty document explaining how to make impressive use . . . to sniff] that their OS offers a proper /net entry in the . . .
4K - last updated 2015-02-24 14:45 UTC by pgas

ListOfPastebins
This is a list of PasteBin URLs that have been used in #awk. There should be a much shorter list of recommended . . . ==== Apparently topic-specific PasteBin services * http://pastebin.bash-hackers.org . . . redirects to the latter. Looks like a Fedora-specific service; it is explicitly under development and . . . - seems to be a Cisco-specific site..? ==== Unverified PasteBin services * http://pastebin.dp.cx . . .
2K - last updated 2015-09-08 09:08 UTC by pgas

logical operator
In [[awk]], *logical operators* are used to perform [[boolean]] operations, and a return a value of [true] . . . [[doubleampersand &&]] | Returns [true] if both [[operand]]s are [[true]], otherwise returns . . . | [[or]] | [[doublepipe]] | Returns [[true]] if either or both [[operand]]s are [[true]], otherwise . . . | [[not]] | [[pling !]] | Returns [[false] if [[operand]] is [[true]], otherwise returns [[true]] . . .
3K - last updated 2009-01-02 11:13 UTC by pgas

LoopOnFields
Fields are numbered from 1 to NF, so you can easily use a for loop, and the derefence operator, for instance . . . matching foo: {{{ awk for (i=1;i<=NF;i++) { if ($i ~ /foo/) { print $i } } }}} . . .
1K - last updated 2009-03-17 21:09 UTC by waldner

LshalOutputParser
=== Problem Specification 10:50 <Thanatermesis> i want to obtain the model of the disk, for example, . . . parenthesized strings that are last on the line if (RLENGTH > 0) { type = substr($2, RSTART+1, RLENGTH-2) . . . = type } function endBlock() { if ("block.storage_device" in PROPERTIES && . . .
3K - last updated 2008-06-27 16:22 UTC by gnomon

Mark Hobley
Welcome to this wiki! Thanks a lot for your contribution. As you seem to start a whole awk guide, maybe . . . read, even more so when the links don't exist. If you fell we need a glossary, we can create a glossary . . .
1K - last updated 2009-01-27 08:04 UTC by pgas

mawk
The **mawk** package provides a very fast awk implementation by Mike Brennan[1] based on a byte code . . . own version of **mawk** called **mawk-2** which differs from the current version developed by Dickey; . . .
1K - last updated 2023-11-23 19:50 UTC by AwkwardCoder

MostrarApostrofos-español
Esta pregunta es tan frecuente que merece su propia respuesta. Y aunque pareciera que esto es una limitación . . . la siguiente solución más obvia - especificar caracteres en hexa - parece funcionar al principio: . . . Group Base Specifications issue 6 (en inglés)]], y reiterado en el . . . '\xHH' es ambigua porque permite especificar más de dos bytes hexadecimales sucesivos. Desafortunadamente . . . los argumentos de acuerdo a la posición especificada en la cadena de formato: {{{ awk 'BEGIN{printf . . .
4K - last updated 2009-01-15 20:03 UTC by fcr

Newline
"print" prints a newline by default. If you don't want a newline, you can use printf instead it is straightforward, . . . #prints the record without adding a newline }}} If you want to join the lines with another characters . . .
1K - last updated 2011-07-05 10:53 UTC by pgas

nudge operator
The *nudge operators* can be used to [[increment]] or [[decrement]] the value of their [[operand]]s, . . . symbol. The nudge [[operator]]s modify their [[operand]]s, so the [[operand]]s must be . . . of their [[operand]]s. === prenudge behaviour If the [[operator]] is used before a [[variable]] name, . . . is 4 and number is 4 }}} === postnudge behaviour If the [[operator]] is used after the [[variable]] . . .
3K - last updated 2011-03-20 13:18 UTC by markhobley

number
== _Numbers can be expressed as integers or floating point values_ In [[awk]], numbers can be expressed . . . point]] values. == _Numbers should be specified in decimal_ The [[awk]] programming language . . . does not provide facilities for specifying numbers in non [[decimal]] bases. However numerical . . .
1K - last updated 2011-03-06 22:33 UTC by markhobley

numeric strings
Numeric strings obtained from the input source, will be treated as numeric values, when compared with . . . and '21'" compare(a,b) } function compare(a,b) { if (a == b) { print "Comparison A: == The values are . . . equal" } if (a != b) { print "Comparison B: != The values are . . . not equal" } if (a > b) { print "Comparison C: > The first . . . value comes after the second" } if (a < b) { print "Comparison D: < The first . . .
5K - last updated 2013-02-24 17:40 UTC by markhobley

oawk
oawk is "old awk", it is the default /usr/bin/awk on Solaris and should not be used. You can also find . . . from this post by Ed Morton]], if you have more please reply to the above thread and/or . . . 1 awk: bailing out near line 1 }}} ==== Hangs if no input and no explicit exit: {{{sh $ time /usr/xpg4/bin/awk . . . array: {{{sh $ /usr/xpg4/bin/awk 'BEGIN{ a[1]=7; if (1 in a) print a[1]; exit }' 7 $ /usr/bin/awk 'BEGIN{ . . . a[1]=7; if (1 in a) print a[1]; exit }' awk: syntax error near . . .
5K - last updated 2012-01-24 08:29 UTC by pgas

oawk or nawk
you can determine if you have oawk or nawk using the following in a BEGIN rule will do the trick. {{{ . . . awk if (ARGC == 0) # old awk else # new awk }}} . . .
1K - last updated 2008-11-19 13:14 UTC by pgas

oawk or nawkJapanese
you can determine if you have oawk or nawk using the following in a BEGIN rule will do the trick. {{{ . . . awk if (ARGC == 0) # old awk else # new awk }}} . . .
1K - last updated 2008-11-24 08:07 UTC by pgas

Overview
= Overview of awk = == The primarily purpose of awk is to processing textual data to produce formatted . . . with each [[pattern]] in the [[script]]. If a [[pattern]] matches the [[input line]], [[awk]] . . . the [[action]] associated with the [[pattern]]. If the line does not match the [[pattern]], the [[awk]] . . . utility takes no action. If more than one [[pattern]] matches the [[input file]], . . . is possible to search one or more files for specified [[pattern]] matches and performing associated . . .
4K - last updated 2011-05-23 23:09 UTC by markhobley

Overview of regular expressions
== What is a regular expression? == A regular expression is a method of representing a string matching . . . within textual data records to be located and modified and they are often used within utility programs . . . types of components: * [[anchor]]s used to specify the position of the pattern in relation to a line . . . or more characters in a single position. * [[modifier]]s used to specify how many times a character . . .
2K - last updated 2011-05-17 20:32 UTC by markhobley

PassingAnArray
* You can use split to create an array from a string: {{{ sh awk -v list='foo,bar,baz' ' BEGIN { n=split(list, . . . map[array[idx]] = k } $0 in map { ... }' }}} * If you want to compare two files with awk (doesn't . . . work if {{{file1}}} is empty). The following code snippet . . .
1K - last updated 2009-04-13 22:51 UTC by goedel

PassingAShellVariable
The common solution is to use the -v option to define an awk variable giving it the value of the shell . . . 'BEGIN{print awkvar}' }}} If you want to pass a pattern as a variable take care . . . -v pattern="$pattern" '$0 ~ pattern{print}' }}} If your variable is an environment variable then you . . . FOO=bar awk 'BEGIN{print ENVIRON["FOO"]}' }}} If this is not enough have a look at the [[http://awk.freeshell.org/comp.lang.awk_FAQ#toc2|comp.lang.awk . . .
1K - last updated 2009-01-30 08:36 UTC by pgas

PasteBin-español
Un PasteBin es un sitio que permite a los usuarios del mismo, pegar tramos de código o texto. Cada tramo . . . solo permite evitar esto, sino que también simplifica el control de versiones, y permite reconstruir . . .
1K - last updated 2009-01-03 03:02 UTC by fcr

pattern
In [[awk]], patterns are used to select lines of input for processing. The pattern within each [[rule]] . . . to take place. The [[action]] only executes if its relevant pattern was matched or the pattern . . . [[bar]] must be in a later [[record]]. If a single record containing both [[foo]] and [[bar]] . . . The [[action]]within a [[rule]] will take place, if the [[expression]] within the pattern evaluates . . . to be true }}} === Omission of the pattern === If a [[rule]] does not include a pattern, then the . . .
2K - last updated 2011-05-19 18:18 UTC by markhobley

precedence
The [[awk]] programming language uses rules of *precedence* to determine the order in which [[operator]]s . . . element of the second element | 5 | x | The fifth component is the [[multiplication]] operator. . . . In cases where two [[operator]]s of different precedences compete for the same [[operand]], . . .
7K - last updated 2013-04-11 06:58 UTC by markhobley

PrimeNumberSieve
This is the standard sieve of Eratosthenes implemented in portable awk. The running time of the bare . . . used (finding primes up to sqrt(bound) and then sifting the remaining segments for O(n) runtime; using . . . to reach sublinear runtime). The main difference between {{{sift1}}} and {{{sift2}}} in the . . . a standard array. The point of implementing {{{sift1}}} in this way was to test whether there would . . . === The Code {{{ #!/usr/bin/awk -f function sift1(N, primes, line, sp, n, i, j) { line = $0; $0 . . .
4K - last updated 2008-06-19 05:56 UTC by gnomon

print
== Usage == === print [ LIST ] === The [[variadic]] **print** function is used to produce simple standardized . . . == Examples == print "Hello" == Default value == If the print function is given no [[argument]] list, . . .
1K - last updated 2011-05-11 15:10 UTC by markhobley

PrintASingleQuote
This question gets asked often enough that it deserves its own answer. This common question doesn't actually . . . can interact badly with the surrounding text in different ways depending on your awk implementation. . . . Group Base Specifications issue 6]], and as reiterated in the GNU . . . more than two successive hex bytes to be specified. Unfortunately the precise behaviour when more . . . printf arguments according to a position specified in the string sequence..: {{{ awk 'BEGIN{printf . . .
5K - last updated 2015-07-05 09:45 UTC by pitman

PrintASingleQuoteJapanese
This page is the translated page of PrintASingleQuote written in Japanese. この問題は何度も質問される内容なので、議論するのに値する問題です。 . . . Group Base Specifications issue 6]] の論理章の 3 段目で記述されているように、GNU awk . . .
3K - last updated 2008-10-15 14:22 UTC by hi saito

printf
== Usage == === printf [ FORMAT, LIST ] === The **printf** [[variadic]] function provides generic [[string . . . for the complete set of ANSI C format specifications together with the %c, %d, %e, %E, %f, %g, . . . %i, %o, %s, %u, %x, %X and %% [[conversion specifier]]s, and the h and l [[conversion qualifier]]s. . . .
2K - last updated 2011-06-09 20:34 UTC by markhobley

PrintfDynamicWidth
With modern awks, you can just do it like you would in C (though the justification is less clear; C doesn't . . . does), like so: {{{ awk maxlen=0 for (i in arr) if (maxlen<length(arr[i])) maxlen=length(arr[i]) . . . }}} With old awks, just do it like you would do if you didn't know about %* (this would be much more . . . in C), like so: {{{ awk maxlen=0 for (i in arr) if (maxlen<length(arr[i])) maxlen=length(arr[i]) . . .
1K - last updated 2008-11-24 08:26 UTC by pgas

PrintfDynamicWidthJapanese
With modern awks, you can just do it like you would in C (though the justification is less clear; C doesn't . . . does), like so: {{{ awk maxlen=0 for (i in arr) if (maxlen<length(arr[i])) maxlen=length(arr[i]) . . . }}} With old awks, just do it like you would do if you didn't know about %* (this would be much more . . . in C), like so: {{{ awk maxlen=0 for (i in arr) if (maxlen<length(arr[i])) maxlen=length(arr[i]) . . .
1K - last updated 2008-11-24 08:36 UTC by pgas

qse
Not a standalone awk, but an interesting library embedding an awk interpreter, from [[https://groups.google.com/group/comp.lang.awk/browse_thread/thread/b02c0d75e49eab75/54fc2c6316d657bc?lnk=gst&q=c%2B%2B+embed#54fc2c6316d657bc| . . . of each other. * running a single script with different I/O streams independently. * changing language . . . (0); /* open a new interpreter */ if (!awk) FAIL ("cannot open awk"); /* parse the hello . . . = QSE_T("BEGIN { print \"hello, world\" }"); if (qse_awk_parsestd (awk, &psin, QSE_NULL) <= . . . QSE_NULL, /* stdin */ QSE_NULL /* stdout */ ); if (!rtx) FAIL (qse_awk_geterrmsg(awk)); retv = qse_awk_rtx_loop . . .
4K - last updated 2011-10-27 06:25 UTC by pgas

RangeOfFields
Printing a range of fields - all fields but the first, for examples, or fields 3 through 8 - is a surprisingly . . . * 2) }}}, another possibility is to shift the fields and adjust NF eg to keep the fields . . . 8: {{{ awk for (i=3;i<=8;i+=1)) $(i-2)=$i # shift $1=$3 $2=$4 ... NF=8-3+1 # only keep the first . . . not the desired behaviour. ==== Using sub() If the separator is the default, you can use a direct . . . number of fields that you want to remove). If you want to remove the last n fields with the same . . .
10K - last updated 2015-09-08 09:52 UTC by pgas

read only variable
=== _User defined variables cannot be marked as readonly_ The [[awk]] extraction and reporting language . . . may be readonly and cannot be explicitly modified from within the [[awk]] script. . . .
1K - last updated 2011-06-01 21:29 UTC by markhobley

ReadDirectory
Getting a list of files in a directory is a tricky process. One might be tempted to try use ls and getline, . . . printf '%s/' *" while (cmd | getline > 0) if ($0) files[n++] = $0 close(cmd) for (f in files) . . . to awk {{{ sh awk "-vdir=$HOME" -f readfiles }}} If you only want directories, use "*/" instead of "*". . . . when there are no files. How can one tell the difference between no files and a single file with the . . .
2K - last updated 2013-10-03 22:35 UTC by emg

Recursively Include C headers
=== Problem Specification i want to generate one big .hpp file out of multiple .hpp files and want to . . . } function print_line(line, f, file) { if (match(line, /^[ \t]*#include[ \ ]*"[^"]+"/)) { . . . "", f) sub(/"/, "", f) file = complete_path(f) if (!(file in list_of_paths)) { list_of_paths[file] . . . print line } function complete_path(file, p) { if (file ~ /^[\/.]/) return file for (i = 1; i <= . . . iplen; ++i) { p = ip[i] if (p == "") p = "." if (p !~ /\/$/) p = p "/" p = . . .
1K - last updated 2011-12-11 05:33 UTC by pgas

redirection
The awk scripting language provides support for redirection via the greaterthan, doublebeak and pipe . . . from a function to be written to a named file. If the named file exists, its contents will be overwritten . . . {{{ awk BEGIN { # Creates a file foobar.txt # If the file already exists, its contents will be overwritten . . .
2K - last updated 2011-06-25 05:12 UTC by pgas

ReferenciarCampos-español
En AWK, $ es el operador para "referenciar campos". Justamente referencia el campo del registro de entrada . . . pero sólo si es distinto del string vacío: if ($i != "") print $i; }}} . . .
1K - last updated 2009-01-03 03:06 UTC by fcr

regular expression operator
The [[awk]] programming language provides a set of *regular expression operators* that have special meanings . . . a match was found. * ~ Returns a value of true if the regular expression matches the left hand operand. . . . {{{ BEGIN { text = "I like banana milkshake" if (text ~ /banana/) { print "Match found" } } }}} . . . operator with a logical not operator: {{{ if (text !~ /strawberry/) { print "Match not found" . . . a rule_ A binding operator is not required if a regular expression is being used as a pattern . . .
2K - last updated 2013-02-19 14:06 UTC by markhobley

RepeatAString
Sometimes it is useful to have something like Perl's 'x' operator, which repeats a string N times. This . . . {{{ awk function rep(str, num, remain, result) { if (num < 2) { remain = (num == 1) } else { remain . . .
1K - last updated 2009-03-01 19:15 UTC by h-67-101-152-180.nycmny83.dynamic.covad.net

return
The [[builtin]] '''return''' [[command]], can be used to exit from a [[function]] within the [[awk]] . . . === Omitting the return value === In [[awk]], if no [[return value]] is specified, then an [[unspecified]] . . . of a [[function]] that returns an [[unspecified]] value. === A function with no explicit return . . . will produce an unspecified value === If the end of a [[function]] block . . . then the [[function]] will return an [[unspecified]] value. . . .
2K - last updated 2011-05-03 17:29 UTC by markhobley

ReverseMapping
{{{ awk # reverse mapping of keys -> values in given array function reverse_mapping(array, tmp_key, . . . in done) delete done[key] for (key in array) { # if we already reversed this pair to avoid a collision, . . . continue if (key in done) continue # if this swap would cause . . . a colision, store those values if (array[key] in array) { tmp_key = array[ key] tmp_element . . . # delete the now old mapping delete array[key] # if we had a collision, reverse those values, too if . . .
2K - last updated 2014-04-23 00:33 UTC by emg

RS
= Record Separator = The [[special variable]] RS is a record separator that is used to determine how . . . in the middle of processing an input file == If the value of the record separator is changed in . . . will always be treated as the end of the record. If the last record is not followed by a blank line, . . .
3K - last updated 2013-02-19 23:11 UTC by markhobley

rule
Scripts in [[awk]] may contain one or more rules. == Rules consist of patterns and actions == Each rule . . . to omitted. === Omission of the pattern === If a [[rule]] does not include a pattern, then the . . . [[input]] line. === Omission of the action === If a [[rule]] does not include an [[action]], then . . .
1K - last updated 2011-05-11 15:07 UTC by markhobley

SandBox
SandBox if you want to test. so now? looks like recaptcha still needed a tweak captcha? ds sds foo bar . . .
1K - last updated 2021-06-21 22:00 UTC by Usernam

SedFAQ
<toc> ---- == I have a line like "abdcgfjeuPATTERNfjfhghj", I want to get the PATTERN part, why . . . working? I get the input line unchanged! If you had the string "foo123bar", and did {{{sed 's/123/123/'}}}, . . . and between any two characters in the string (if it cannot match a longer string, of course). /b*/ . . . comes into play in case many matches of different lengths are possible //**starting at that . . . beginning, and there is no alternative between different match lengths: only a match of length 0 is . . .
34K - last updated 2010-02-14 17:56 UTC by waldner

ShellQuoting
Quoting can be such a headache for the novice, in shell programming, and especially in awk. Art Povelones . . . probably too much detail to repeat with the FAQ; if you could use it, search via <http://groups.google.com/>. . . . awk -f /tmp/never$$.awk; rm /tmp/never$$.awk }}} If you enjoy testing your shell's quoting behavior . . . 7-quote example: note that it is quoted three different ways: {{{ awk 'BEGIN { q="' "'" '";print "Never . . .
2K - last updated 2008-11-19 07:41 UTC by pgas

Shells
The examples using quoting are intended for use with any standard (sh-compatible-quoting) Unix shell. . . . instead. Non-sh-compatible shells will require different quoting. If you're not even using Unix (or . . .
1K - last updated 2008-11-19 07:37 UTC by pgas

ShellsJapanese
The examples using quoting are intended for use with any standard (sh-compatible-quoting) Unix shell. . . . instead. Non-sh-compatible shells will require different quoting. If you're not even using Unix (or . . .
1K - last updated 2008-11-24 08:04 UTC by pgas

SimpleCalc
Simple 4 operations calculator ... {{{ awk # usage: print calc("5 * (1 + 2) * 5 + 7") # reads and update . . . next_token(s, t) { sub(/^[[:space:]]*/,"", s[0]) if (match(s[0], /^[()]/) || match(s[0], /^[-+]?[0-9]+(\.[0-9]+)*/) . . . s[0] = input while (token = next_token(s)) { if (token ~ /^[-+]?[0-9]+(\.[0-9]+)*/) { postfixed[++len] . . . = token } else if (token ~ /[-+/*]/) { while ((head > 0) && . . . head-=1 } stack[++head] = token } else if (token ~ /[(]/) { stack[++head] = token } else if . . .
2K - last updated 2015-09-10 06:14 UTC by pgas

SolarisNawk
I want to use the tolower() function with {{{SunOS}}} nawk, but all I get is {{{ nawk: calling undefined . . . available awks, or or use /usr/xpg4/bin/awk (if you have it), or write your own function to do it . . . supposed to conform to the single > unix specification. No one knows why Sun continues to ship old . . .
1K - last updated 2008-11-24 08:24 UTC by pgas

SolarisNawkJapanese
I want to use the tolower() function with {{{SunOS}}} nawk, but all I get is {{{ nawk: calling undefined . . . available awks, or or use /usr/xpg4/bin/awk (if you have it), or write your own function to do it . . . supposed to conform to the single > unix specification. No one knows why Sun continues to ship old . . .
1K - last updated 2008-11-24 08:36 UTC by pgas

SpecialFile
You can use `-v rulesfile=filename' to process a file differently, like you would any other variable, . . . in your BEGIN statement. {{{ awk BEGIN \ { if (rulesfile=="") { print "must use -v rulesfile=filename"; . . . >0 ) replace[$1]=$0; close(rulesfile); } { if ($1 in replace) print replace[$1]; else print; } . . .
1K - last updated 2008-11-18 13:37 UTC by pgas

SpecialFileJapanese
You can use `-v rulesfile=filename' to process a file differently, like you would any other variable, . . . in your BEGIN statement. {{{ awk BEGIN \ { if (rulesfile=="") { print "must use -v rulesfile=filename"; . . . >0 ) replace[$1]=$0; close(rulesfile); } { if ($1 in replace) print replace[$1]; else print; } . . .
1K - last updated 2008-11-24 08:09 UTC by pgas

SplitIntoChars
In portable POSIX awk, the only way to do this is to use substr to pull out each character, one by one. . . . 5 elements -- "c", "h", "a", "r", "s". If you don't have any ^As in your string, you could . . .
1K - last updated 2008-11-24 08:20 UTC by pgas

SplitIntoCharsJapanese
In portable POSIX awk, the only way to do this is to use substr to pull out each character, one by one. . . . 5 elements -- "c", "h", "a", "r", "s". If you don't have any ^As in your string, you could . . .
1K - last updated 2008-11-24 08:35 UTC by pgas

StupendousSedSwitch
Although not strictly pertinent to the goings on in {{{#awk}}}, there is a significant overlap of those . . .
2K - last updated 2009-09-14 22:13 UTC by gnomon

StyleSheet
body { background-color:#FFF; color:#000; margin:1em 2em; } textarea { width:100%; } a:link { color:#00F; . . . right; clear: right; border-style:none; } div.diff { padding-left:5%; padding-right:5%; } div.old . . . } @media print { body { font:12pt sans-serif; } a, a:link, a:visited { color:#000; text-decoration:none; . . . } table.user td.j { text-align:justify; } table.user td.mark { background-color:yellow; . . . max-width: 530pt; } BODY,TD,P { text-align: justify; font-size: 10pt; line-height: 14pt; font-family: . . .
5K - last updated 2008-06-19 16:46 UTC by pgas

text.2.wiki.awk
#:       C:\#\awk\lib\text.2.wiki.awk\\ . . . if(_debug)   for(i in B)   { print(_qt_(++j, . . . if(_debug)   for(i in A)   { print(_qt_(++k, . . . for(i in A)   if(tolower($1) == i)   {\\               . . . if((! _in_escape) && (A[i] == _esc1)) . . .
11K - last updated 2012-09-24 14:55 UTC by g0ph3r

text 2 wiki.awk
{{{ #: C:\#\lib\awk\utl\text_2_wiki.awk #: 2012-09-15 23:40:11 #:rod.t_2012 #: This file is http://awk.freeshell.org/text_2_wiki.awk . . . > NUL: ## _____ { if($0 ~ /\\\\$/) { s = $0; } else if($0 ~ /`$/) { s . . .
2K - last updated 2012-09-16 09:12 UTC by g0ph3r

tilde
== Substring containment operator == The tilde [[symbol]] can be used as a containment operator providing . . . a [[pattern]] match if a string matches a [[regular expression]]: === Non . . .
1K - last updated 2011-05-19 19:04 UTC by markhobley

tracert.awk
{{{ awk #:: C:\_\_u\tracert.awk #: 2014-07-06 19:47:02 #:: rod.t_2014 #:: extract basename for tracert . . . = "C:/_/_u/tracert.awk"; _awk = ARGV[0]; if(_env("ComSpec")) { system("norm.exe"); #:: restores . . . window if minimized/hidden _cmd = "tracert "; _con = "CON:"; . . . _awk = tolower(_awk); if((_awk !~ "gawk") && \ (_awk !~ "mawk")) . . . '+%Y-%m-%d__%H:"; _dtcmd = _dtcmd "%M:%S.00'"; } if(cmd) _cmd = cmd; print("\n\t" _dt() "\t" _awk, "-f . . .
4K - last updated 2014-07-07 06:15 UTC by 212.205.56.222

truth
== Boolean Truth == A **boolean [[expression]]** has only two outcomes: **true** or **false**. In [[awk]], . . . thus awk will not complain: {{{ sh $ awk 'BEGIN{if (true) {print "true"} else {print "false"}}' false . . . used. ==== Taking zero from the data source If a value of "0" or "000" or " 00", is taken from . . . and it evaluates to false: {{{ sh echo 00 | awk'{if ($1) {print "true"}else{print "false"}}' false # . . . number 0 }}} ==== Taking zero from a variable If a zero value is assigned to a variable, it may be . . .
3K - last updated 2013-02-20 17:34 UTC by markhobley

UserPages
User pages are useful to present yourself, add your personal possibly off topic rant start a discussion . . . |title of this page]] Also if you use this name in the Username box when editing . . .
1K - last updated 2008-12-31 09:58 UTC by pgas

variable
A '''variable''' is a symbolic name associated with a [[value]]. A variable acts as a container and the . . . This means that variable names that have different letter cases are distinct and separate from . . . each other: {{{ # The identifiers dog,Dog and DOG represent separate variables . . . that newstr = "hello " name; print newstr; }}} If the print statement is given several arguments (that . . .
3K - last updated 2012-04-22 11:42 UTC by unregistered

VariablesInRegex
The patterns between slashes like /pattern/ are called **ERE constants**, or **regular expressions literals**. . . . contain fixed, constant regular expressions. If you have a variable //var// that contains "**abc(123)?r+**" . . . expected, like this: {{{ awk var="abc(123)?r+" if ($1 ~ var){ # $1 matches, do something } }}} or . . .
2K - last updated 2010-11-26 08:49 UTC by 195.97.26.99

WartAndWishList
Awk is a wonderful language! That said, there are a few annoying bits... == The Good * well-documented . . . good consistency between them * terse domain-specific syntax * rapid execution, fast startup * awk is . . . but rarely-used odds and ends (like the specific escape sequences for strftime and [s]printf) == . . . The Bad * It's quite difficult to map back from the auto-split fields to . . . mentions that it may be easier to remember if one thinks of it as the {{{string ~ pattern}}} matching . . .
7K - last updated 2009-04-13 18:39 UTC by goedel

What is awk
awk is an extraction and reporting language, named after its three original authors: * Alfred V. **A**ho . . . I didn't write just because I'm distributing it. if you have a review you'd like me to put a pointer . . .
5K - last updated 2014-11-28 08:24 UTC by pgas

What is awkJapanese
awk is a programming language, named after its three original authors: * Alfred V. Aho * Brian W. Kernighan . . . I didn't write just because I'm distributing it. if you have a review you'd like me to put a pointer . . .
2K - last updated 2008-11-24 08:03 UTC by pgas

WhenAreTheFieldsSet
Basically, you should set FS before it may be called upon to split $0 into fields. Once awk encounters . . . $1 } }}} e.g., {{{ awk -F: '{ print $1 }' }}} if you run code like this {{{ awk { FS=":"; print $1 . . .
1K - last updated 2008-12-15 12:46 UTC by pgas

WhichIsBetter
This comes up so often that it deserves a page on its own. **NEVER**, **EVER** ask computer people whether . . . and "better" are quite generic words that mean different things to different people. In no particular . . . * interoperable * compliant (to some specification) * understandable * works with your hardware . . . generic and in many cases would need further clarification if occurring in a conversation, even (or . . . "is X better than Y?" is going to get you indifference (if you're lucky), or downright rude answers . . .
5K - last updated 2009-07-12 09:13 UTC by host-87-74-84-72.dslgb.com

XMLScraping
You cannot easily parse xml with awk. But there are several tricks to scrap an xml file: <toc> . . . 'NF>1{print $2}' }}} This can be generalized if you have more than one pair of <tag> on the . . . print $i}' }}} ==== <tag> </tag> different lines * Simplest answer: {{{ sh awk '/<tag>/,/<\/tag>/' . . . }}} * The above solutions only work if there is nothing on the line after tag. If this . . . Extracting the value of the attribute foo ==== if you want all the foo disregarding the tag * one . . .
2K - last updated 2011-11-23 15:06 UTC by pgas

154 pages found.