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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 . . . variables: ARGC ARGV FNR RSTART RLENGTH SUBSEP\\ . . . https://github.com/danfuzz/one-true-awk\\ [4] first? commercial awk for ibm pc - sold back to Thomson\\ . . . [6] often the fastest\\ . . .
2K - last updated 2013-10-26 02:28 UTC by g0ph3r
AA-awk-one-page
http://awk.freeshell.org/AA-awk-one-page\\ 2013-09-19 20:23:02 http://awk.freeshell.org/g0ph3r\\ attempt . . . source: ftp://ftp.gnu.org/gnu/gawk/\\ . . .
2K - last updated 2013-09-20 06:55 UTC by g0ph3r
Adler32Checksum
As documented in the [[http://en.wikipedia.org/wiki/Adler-32 | Adler-32 Wikipedia article]]. {{{ awk . . . be 5552 when almost every # modern awk has numbers with at least 53 bits of precision, but # if we . . . and also easy # for other searchers to find this code. And, really, this choice # of . . . string keys, every # index into an array incurs the constant overhead of the # string hash function. . . . our keys # here are strings; if they were numbers, we would also # have to convert those numbers to . . .
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 . . . and "bad" or "wrong" uses of getline. Of course, although the author is a well-known and authoritative . . . input from many of the comp.lang.awk regulars, including Steve Calfee, Martin Cohen, Manuel Collado, . . . Jürgen Kahrs, Kenny Mc{{{}}}Cormack, Janis Papanagnou, Anton . . . was designed to read input. It's like C programmers continuing to do procedural programming in C++ rather . . .
16K - last updated 2009-02-15 22:14 UTC by waldner
arithmetic
The [[awk]] programming language provides a set of [[dyadic]] arithmetic operators for performing basic . . . operator. ---- [[Calculations involving integers may produce floating point results]] [[precedence]] . . .
1K - last updated 2011-05-24 22:16 UTC by markhobley
ArrayLength
Posix does not define a way to get the length of an array, while you could use a loop to count the elements . . . usual strategy is to keep track of the length yourself. {{{ awk #using a counter a[n++]="foo" a[n++]="bar" . . . This problem is fixed in the gawk-stable CVS version available from savannah.gnu.org. . . .
2K - last updated 2009-02-09 09:45 UTC by arnold.robbins
awk-glossary
concise glossary of the essential awk - Last edited 2014-08-04 02:26 UTC\\ Contents: . . . AWK versions, Docs, References, People, . . . History.\\ ---- AWK versions:\\ bwk-awk: . . . ))\\ gawk: gnu version of awk\\ https://www.gnu.org/software/gawk/\\ . . . version 1.3.4: http://invisible-island.net/mawk/\\ . . .
5K - last updated 2014-08-04 03:23 UTC by y0tta
awk.exe
[[awk.exe]] Last edited 2013-05-27 23:57:16 PDT\\ The first is from Dr. Kernighan - the k of awk.\\ gawk . . . version 20070501\\ from: http://www.cs.princeton.edu/~bwk/btl.mirror/index.html\\ . . . http://awk.freeshell.org/FIXES\\ \\ awk64.exe version 20110810\\ (code from above site; 64 bit version)\\ . . . \\ gawk.exe version 4.1.0\\ (compiled with mingw)\\ from: http://sourceforge.net/projects/ezwinports/files/\\ . . . (klabaster version has no MPFR)\\ docs: http://www.gnu.org/software/gawk/manual/\\ . . .
2K - last updated 2013-05-28 07:57 UTC by g0ph3r
awk1page
an awk program is a series of //pattern { actions }// statements;\\ ie if the input line matchs pattern . . . fields separated by whitespace - $1 is the first field; $2 the second ...\\ and $0 is the whole . . . {{{awk # print those lines where "awk" appears in the first field. $1 ~ /awk/ { print $0; } }}} . . . all data is read; so to print the sum of the first column: {{{awk { sum = sum + $1 } END { print sum . . . = " sum; print "max value = " max; } }}} For terse concise summary see:\\ http://www.cs.princeton.edu/courses/archive/spring12/cos333/awk.help\\ . . .
2K - last updated 2012-03-18 22:22 UTC by g0pher
awk 2012 ISO
**[[awk_2012_ISO]]** revised: . . . The first meeting of the committee will be on //**2012-04-01**//\\ . . .
4K - last updated 2012-09-16 03:39 UTC by g0ph3r
awk Lucent Copyright notice
file FIXES from http://www.cs.princeton.edu/~bwk/btl.mirror/awk.zip ; version 20110810 {{{awk /***** . . . made since the AWK book was sent to the printers in August, 1987. Aug 10, 2011: }}} . . .
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) . . . the original was called oawk\\ and the new version nawk.\\ it has been a major source of confusion . . . page v: original in 1977 / new version in 1985\\ page vi: This version in System V Rel . . . atan2 sin cos rand srand match sub gsub\\ vars: ARC ARGV FNR RSTART RLENGTH SUBSEP\\ keywords: . . .
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 . . . with both gawk and POSIX (libmawk, of course, should have the same compatibility as [[mawk]]). . . .
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] . . . for the GNU extensions. awk native internal numbers will be used in this first version, with the LargestAccurateNumber . . . of fast-path cases where native awk numbers can be used instead of bignums for speed gains There . . . line to go with this roadmap. Notably, this version of dc is intended to include tail-call elimination . . . for macro calls. Tail recursion drops out of this optimization as a special case . . .
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 . . . |=Special characters in RE (\w etc.)|no|yes (but not in POSIX mode)|yes|no|no|no|unknown|no|no|no| . . . |=using empty FS to split characters|no (undefined)|yes, but not in POSIX mode|yes|yes|no|no|unknown|no|no|yes| . . . |=split() splits chars with empty sep|undefined|yes (both with ~// and . . . regex (see sample code)|yes| |=using a regex for RS|no (undefined)|yes, even in POSIX mode!|yes|yes|no|no|unknown|no|no|no| . . .
4K - last updated 2015-04-27 13:23 UTC by pgas
AwkGuide
** Work in Progress ** {{{ import from Mark Hobley's wiki }}} <toc> ---- == Overview * [[Overview]] . . . When to use awk * [[When to use awk]] == Which version of awk should I choose? * [[Which version of . . . function]]s * [[calling section]] * [[case conversion]] * [[case sensitivity]] * [[caveat]]s * [[close]] . . . character * [[control structure]]s * [[conversion qualifier]]s * [[conversion specifier]]s * [[datatype]]s . . . * [[file]] handling * [[floating point]] numbers * [[for loop]]s * [[foreach]] loops * [[FS]] * [[function]]s . . .
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)} . . . Seven so suspect is ok for XP and Vista. Other versions of awk include [[http://www.gnu.org/software/gawk/manual/| . . . ----\\ awk95.exe is Windows 32 executable - version 20071023\\ http://www.cs.princeton.edu/~bwk/btl.mirror/awk95.exe\\ . . . with Microsoft Visual C++\\ (awk95.exe -version says 20070501 but it is the 20071023 version) . . . AWK Programming Language" book\\ ----\\ Win32 versions of awk (bwk-princeton) 20100228, gawk 3.1.7, . . .
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 . . . var=value] [-f progfile | 'prog'] [file ...] -version or --version; print version and exit; (was -V; . . . prints: awk version 20070501 But is actually 20071023 version) - . . . SYMTAB[varname]) The `**' and `**=' operators are valid instead of ^ #: system() returns errorcode/256 . . . then message #: regular expression metacharacters: \ . ^ $ [ ] | + * ? ( ) #: filenames may Not contain: . . .
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 . . . kind of awk-grep, if you like). A reasonable first shot is usually something like {{{ awk '{if ($0 . . . but there are a number of things to note. The first thing to note is that it is not structured according . . . the line awk '$0 = NR" "$0' # prepends line numbers (assignments are valid in conditions) awk '!a[$0]++' . . . file, starts again from 1 as soon as the first line of the next file is read, and so on. So, the . . .
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, . . . the authors of perl have usually known awk (and sed, and C, . . . perl has built-in support for that almost no version of awk can do without great difficulty (if at . . . no choice to make. For instance, no reasonable person would try to write a web server in awk instead . . . important if deciding which to learn first) * awk syntax is far more regular (another advantage . . .
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, . . . the authors of perl have usually known awk (and sed, and C, . . . perl has built-in support for that almost no version of awk can do without great difficulty (if at . . . no choice to make. for instance, no reasonable person would try to write a web server in awk instead . . . important if deciding which to learn first) * awk syntax is far more regular (another advantage . . .
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 . . . you want with awk. Following are some hints: * First and easiest answer (requires GNU awk): use gensub(). . . .
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 . . . you want with awk. Following are some hints: * First and easiest answer (requires GNU awk): use gensub(). . . . backreferences natively. Example: {{{ awk # reverse letter and following digit and insert "+" if letter . . . can use the possibility to assign a regexp to RS to "pull out" substrings from the input (and without . . .
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 . . . dollar sign }}} To get behavior like the first case in a string, use {{{"\\\\$"}}} . There are . . . other, less obvious characters which need the same attention; under-quoting or . . . for alternation: {{{ /\(test\)/ => 6 characters `(test)' "\(test\)" => /(test)/ => 4 characters . . . regarding different forms of special characters; POSIX requires that {{{`\052'}}} be treated as . . .
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, . . . could be to use a hash to store the numbers of the records to print: i) Print the Nth record . . . pattern contains regular expression metacharacters, so in that case index() can be used instead (thanks . . .
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** . . . and are executed once only before the first [[input]] record is read. Begin blocks are prefixed . . . used to initialize [[variable]]s, such as the [[RS|record separator]] and [[FS|field separator]], but . . . BEGIN { # This is a begin block print "The awk parser" # Print the title # Set the field separator to . . . effects Begin blocks are executed before the first input record is read, so there is no current record . . .
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 . . . * [[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 . . . [[if]], [[else]] === Using logical operators === The [[awk]] extraction and reporting language . . . conditional branching using logical operators. . . .
1K - last updated 2011-04-17 06:37 UTC by markhobley
bwk
===bwk awk=== The original implementation of awk. Named after the initials of its primary author, Brian . . . Many historical versions are available in the git repository at [[https://github.com/danfuzz/one-true-awk]]. . . .
1K - last updated 2013-04-12 19:52 UTC by 67.80.208.web-pass.com
CAAN-or-caan
**caan: the comprehensive awk archive network**\\ -or-\\ . . . Intro, Archives, Versions, Etc, EOF**\\ ---- **Intro:**\\ . . . help: http://www.cs.princeton.edu/courses/archive/spr14/cos333/awk.help\\ primer: . . . as a single pdf file: goebel's http://www.vectorsite.net/tsawk.html\\ tutorial: http://www.gnu.org/software/gawk/manual/html_node/Getting-Started.html\\ . . . ---- **Versions:**\\ bwk-awk: http://www.cs.princeton.edu/~bwk/btl.mirror\\ . . .
4K - last updated 2014-05-29 02:01 UTC by g0ph3r
case conversion
The [[awk]] extraction and reporting language provides the toupper and tolower functions for converting . . . === The tolower function returns a lowercase version of the STRING argument. This function converts . . . all letters to lowercase in the returned string. Only the returned . . . === The toupper function returns a lowercase version of the STRING argument. This function converts . . . all letters to uppercase in the returned string. Only the returned . . .
2K - last updated 2011-06-25 05:10 UTC by pgas
case sensitivity
== Indentifier names == The [[awk]] interpreter is lettercase sensitive. This means that [[variable name]]s . . . separate from each other: {{{ awk # The identifiers dog,Dog and DOG represent separate variables BEGIN . . .
1K - last updated 2011-06-25 05:14 UTC by pgas
CAWKLib
=CAWKLib CAWKlib is a library of functions for for awk intended to be used with preprocessors/wrappers . . . BangCAWK and thanks to some insight from others (thanks Ben) they were eventually pulled out into . . . *str_capitalize() -- returns a string with the first character capitalized and the rest lowercase. If . . . specified it is used as a separator and every first character after that separator character is capitalized. . . . repeat a string up to a certain length *str_reverse() -- revers a string *str_squeeze() -- reduce successive . . .
5K - last updated 2015-01-29 10:14 UTC by 108-243-116-77.lightspeed.cicril.sbcglobal.net
ChannelRegulars
List of regulars in no particular order: * axisys * galaxywatcher * gnomon * gnubien * goedel * {{{go|dfish}}} . . . * inv_arp * karolisl * mike (of the many underbars) * paul * pgas * [[http://eugeneciurana.com|pr3d4t0r]] . . .
1K - last updated 2011-11-14 15:34 UTC by galaxywatcher
Columnate
This script columnates the input file, so that columns line up like in the GNU column(1) command. Its . . . output is like that of **column -t**. First, awk reads the whole file, keeps track of the maximum . . .
1K - last updated 2009-02-28 21:32 UTC by h-67-101-152-180.nycmny83.dynamic.covad.net
command line parameter
The [[awk]] extraction and reporting language uses traditional conventions for accessing command line . . . parameters. The command line arguments are stored in the [[array]] . . . ARGV, and the number of parameters are stored in the [[scalar]] variable ARGC. {{{ . . . { print "There are " ARGC "command line parameters" for(l=1; l<ARGC; l++) { print "Argument " l . . .
1K - last updated 2011-06-25 05:49 UTC by pgas
comment
Comments are pieces of text or [[whitespace]] that can be included in a program to make the code more . . . understandable to a programmer. Comments have no effect . . . ignore the [[hash]] symbol and any other characters that follow it until the end of the line: {{{ # . . .
1K - last updated 2009-07-15 17:07 UTC by MarkHobley
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/ . . . == How does awk deal with multiple files? === Version warning Some of these techniques will require . . . non-ancient versions of awk. === How can awk test for the existence . . . Edit this answer]] === How can I treat the first file specially? <include "FirstFile"> [[http://awk.freeshell.org/?action=edit;id=FirstFile| . . . ---- == How can I split a string into characters? <include "SplitIntoChars"> [[http://awk.freeshell.org/?action=edit;id=SplitIntoChars| . . .
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/ . . . == How does awk deal with multiple files? === Version warning Some of these techniques will require . . . non-ancient versions of awk. === How can awk test for the existence . . . Edit this answer]] === How can I treat the first file specially? <include "FirstFileJapanese"> . . . [[http://awk.freeshell.org/?action=edit;id=FirstFileJapanese| Edit this answer]] === How can I explicitly . . .
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 . . . String comparison In awk, the comparative operators can be used to compare strings for lexical equivalence . . . or ordering. The string matching operators are case sensitive and the behaviour of the comparative . . . operators depends on the locale being used. The following . . . are not equal" } if (a > b) { print "The first string is lexically after than the second" } if . . .
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 . . . first file into an array. Let's say for instance we have . . . a list of first names in file1, one per line: {{{ John Mary }}} . . . find the names in file2 corresponding to the first name in file1. This can be done in a compact manner . . . records in the file. This is only true for the first file, for the second file NR will be equal to the . . .
2K - last updated 2011-08-25 00:35 UTC by steve
compound assignment operator
The *compound assignment operators* (also called *combination assignment operators*) provide a more concise . . . should be taken when compound assignment operators are used within an [[expression]]. Without [[parentheses]], . . . the compound assignment operators may have a lower [[precedence]] than the other operators . . . There are no logical compound assignment operators in awk === The awk extraction and reporting language . . . support for logical compound assignment operators: {{{ # This will not work because there are # no . . .
2K - last updated 2011-03-27 09:46 UTC by markhobley
ConcatenationPrecedence
You'd expect `6 -22', but you get `6-22'. It's because the `" " -22' is grouped first, as a substraction . . .
1K - last updated 2008-12-15 12:37 UTC by pgas
continuation
Line continuation enables long lines of code to split across several lines for the purpose of making . . . World!" exit } }}} === Continuation characters must be appropriately placed within a statement . . .
1K - last updated 2011-05-09 22:48 UTC by markhobley
ConvertHexToFloatingPoint
This code uses [[gawkism|gawk specific features]], such as the [[http://www.gnu.org/manual/gawk/html_node/Strtonum-Function.html][strtonum]] . . . on fp conversion by Orley and Matthews]]. = AWK Code {{{ # function . . . to convert 4 "bytes" of hex chars into a floating point # bytes are ordered # [high....low] . . . bias=127 # convert the character bytes into numbers i3=strtonum("0x" b3) i2=strtonum("0x" b2) i1=strtonum("0x" . . . b1) i0=strtonum("0x" b0) # first, we need to separate all the parts of the floating . . .
3K - last updated 2010-06-23 19:49 UTC by john b
dollar
== Prefixing field numbers == The dollar symbol can be used to prefix [[field]] numbers: == Regular expression . . .
1K - last updated 2010-11-28 10:46 UTC by markhobley
dollarint
A [[dollar]] sign and followed by an [[integer]] are used to refer to [[field]]s within the current [[record]]: . . . behaves like the * on a pointer. == Field numbers are not limited to single digits == Unlike the positional . . . parameters in the Unix shell, fields are not limited to single . . . } # output field number 123 }}} == Field numbers do not need to be constant == The field number after . . . will produce an [[empty string]]. === Field numbers must be positive === It is not permissible 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, . . . If you have special requirements, you can of course use something more sophisticated like mktemp to . . .
1K - last updated 2009-04-11 17:29 UTC by waldner
END
The [[awk]] programming language allows us to use **end blocks** to provide [[finishoff]] and [[cleanup]] . . . read. == Programming Convention The original version of [[awk]] required the *end block* to be placed . . . is no longer a requirement of current [[awk]] versions, however it is recommended that this convention . . .
2K - last updated 2011-04-30 22:52 UTC by markhobley
ENVIRON
Modern versions of new awk (gawk, mawk, Bell Labs awk, any POSIX awk) all provide an array named ENVIRON. . . . a better awk. There are many freely available versions. Longer answer, on Unix you can use a pipe from . . .
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. . . . a better awk. There are many freely available versions. Longer answer, on Unix you can use a pipe from . . .
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 . . . unless it is the only one supported by your version of awk (which, in that case, should be upgraded . . . 3** RTFM if your awk can access enviroment vars. Then perhaps {{{ awk -F: '$1 ~ ENVIRON["USER"] . . . also works with ksh and some other shells. The first approach is extremely portable, but doesn't work . . .
3K - last updated 2011-07-05 09:31 UTC by pgas
escape sequence
Some characters cannot be included in [[literal string]]s, because they are [[nonprintable]] or [[control . . . character]]s, or characters that affect [[delimit]]ation of the strings, such . . . as [[quotation mark]]s. These characters can be inserted by using an *escape sequence* (known . . . symbol can be used to insert literal characters into a string An *escape sequence* consists of a . . . symbol followed by a character or set of characters used to represent the literal character using a . . .
3K - last updated 2008-12-30 13:07 UTC by Mark Hobley
ExitCode
Normally, the `exit' command exits with a value of zero. You can supply an optional numeric value to . . . exit 12; }}} If you have an END block, control first transfers there. Within the END block, an `exit' . . .
1K - last updated 2008-11-26 12:30 UTC by pgas
exponent
==Warning! The use of [[gawkism]]s will prevent the script from running correctly on systems that use . . . than all other [[arithmetic]] operators: {{{awk print (2 * 4 ** 3) # 128 the exponent has . . . operator]] gawkism represented by a [[starstarequals]] trigraph, can also be used to perform . . .
2K - last updated 2012-03-20 07:33 UTC by g0pher
fcr
== Francisco Castro Buenas, me presento, soy Francisco Castro, conocido en el irc como fcr (la sigla . . . podrán encontrar información personal, y sobre algunos de los proyectos en los que . . .
1K - last updated 2009-02-13 07:45 UTC by pgas
field reference
== The field reference operator == The [[dollar]] symbol acts as a unary *field reference operator* and . . . } # output field number three }}} === Field numbers are not limited to single digits === Unlike the . . . positional parameters in the Unix shell, [[field]] numbers are not limited . . . } # output the entire record }}} === Field numbers must not be negative === It is not permissible to . . . use negative field numbers. Attempting to reference a negative field number . . .
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 . . . or constant. E.g. if you want to print the first field, the following are equivalent: {{{ # print . . . the first field using the '$' operator and a constant. print . . .
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 . . . bit.txt is always equal to NR - that is, the first field on each line of bit.txt is simply the line . . . -f BEGIN { BIT = "bit.txt" FILE = "file.txt" ERRSTR = "Guarantee violated, no value for %s in %s (%s, . . . > 0) print (($3 in BL) ? BL[$3] : sprintf(ERRSTR, $3, BIT, FILE, $1)) close(FILE) # equivalently . . . assumes that bit.txt is already sorted on the first # field. Since that first field is supposed to . . .
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. {{{ . . . ret; } }}} [ I've read reports that earlier versions of mawk would write to stderr as well as getline . . .
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. {{{ . . . ret; } }}} [ I've read reports that earlier versions of mawk would write to stderr as well as getline . . .
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 . . . may contain backslash-escaped quote characters. An easy way of doing this is..: # find the index . . . character; # perform a values-to-keys inversion on the preceding array so that you then have . . . a list of positions that point to sequence numbers; # find the index of every backslash character; . . . 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 . . . = 0 # optional: used if start[] is needed a = RSTART; b = RLENGTH # to avoid unexpected side effects . . . (match(str, re) > 0) { arr[++j] = substr(str, RSTART, RLENGTH) # start[j]=RSTART+eaten # optional: . . . save position of match in the string # eaten+=(RSTART+RLENGTH-1) str = substr(str, RSTART+RLENGTH) . . . } RSTART = a; RLENGTH = b return j } }}} TODO: correctly . . .
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 . . .
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 . . .
1K - last updated 2008-11-24 08:09 UTC by pgas
FIXES
[[FIXES]] revised: . . . printers in August, 1987."\\ (( . . . (p 63).\\ added some missing ansi printf conversion letters: %i %X %E %G.\\ no . . . %* conversions work. (Jun 14, 1989)\\ added -v x=1 ... for . . . 1993)\\ delete arrayname is now legal; it clears the elements but leaves\\ the . . .
6K - last updated 2014-01-15 23:17 UTC by g0ph3r
FNR
The *FNR* informative [[special variable]] is used to track the number of [[record]]s that have so far . . . when a new file is started. === Adding line numbers to a file === The FNR [[special variable]] can be . . . wielded to give a simple way of adding line numbers to a file using [[awk]]: awk '{print FNR,$0 }' filename . . .
1K - last updated 2011-05-08 11:04 UTC by markhobley
ForceNumeric
These are the canonical, work-in-all-versions snippets. There are many others, most longer, some shorter . . . less portable). To compare two variables as numbers ONLY, use {{{ awk if (0+var1 == 0+var2) }}} To compare . . .
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 . . . is intended to be read by a human rather than parsed by a program. You can use awk to format the output . . .
1K - last updated 2008-11-29 05:22 UTC by gnomon
Frequently Asked Questions
Some entries of this page have been copied from the [[comp.lang.awk_FAQ]]([[http://awk.freeshell.org/comp.lang.awk_FAQ#toc29|Credits]]) . . . instead of 1000001.10? <include "PrintingNumbers"> [[http://awk.freeshell.org/?action=edit;id=PrintingNumbers| . . .
3K - last updated 2015-09-08 08:46 UTC by pgas
FS
= Field Separator = The [[special variable]] FS is a field separator that is used to determine how [[awk]] . . . often separated by multiple whitespace characters, rather than a single space. The awk interpreter . . . spaces from being interpreted as separators delimiting an empty field. Note that only a single . . . case in this manner. Any other single characters would be treated as delimiters for an empty field: . . . five fields, because groups of other delimiters are treated as separating empty fields echo "Rhubarb##Custard##Bananas" . . .
5K - last updated 2013-02-19 21:45 UTC by markhobley
g0pher
Notes: [[g0pher]] from [[irc://irc.freenode.net//#awk|#awk channel on freenode]]. *Latest (2012-03-18) . . . [[awk1page]] and [[awk_nawk_oawk]] **For terse concise summary see: [[http://www.cs.princeton.edu/courses/archive/spring12/cos333/awk.help|awk.help]] . . .
2K - last updated 2013-05-28 04:13 UTC by g0ph3r
gawk
===gawk=== The [http://www.gnu.org/software/gawk/|GNU] version of awk. It features decent compatibility . . . (and other) extensions. This is likely the version of awk most people are familiar with if they . . .
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 . . . function * [[nextfile]] * [[newline]] characters after certain [[symbol]]s and [[keyword]]s are ignored . . . * [[pipeand]] operator * [[PROCINFO]] * [[RS]] can be a [[regular expression]] * [[rshift]] (bitwise . . . * [[strtonum]] function * [[TEXTDOMAIN]] * underscore string prefix (for translation) * [[xor]] (bitwise . . .
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. . . . to emulate most of sed's features with awk. First, we will discuss how to emulate sed with awk (specifically, . . . faithfully in awk using sub() (to replace the first occurrence of the regexp, like sed 's/foo/bar/') . . . { # here we just use the uppercase version of the matched # strings as a replacement, but . . . code to emulate this sed command: {{{ # reverse letter and digit and insert "+" if letter is "a" . . .
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 . . . http://en.wikipedia.org/wiki/Grace_Murray_Hopper_Award\\ . . . DEC RSX11M, VMS, Windows NT 1942-\\ http://en.wikipedia.org/wiki/Jeffrey_Ullman . . .
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 . . . %s\n\n", host |& socket for (header in headers) { printf "%s\r\n", headers[header] |& socket . . .
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 . . . | foobar === Failure === If a [[failure]] occurs during the [[getline]] operation, the special variable . . . with a [[fatal]] error. However, some versions of [[awk]] do not [[abort]] following the [[failure]] . . .
1K - last updated 2011-05-02 20:14 UTC by markhobley
GettingStarted
[[GettingStarted|GettingStarted]] {{{ first - do not be afraid - nothing here will hurt your system }}} . . .
1K - last updated 2010-10-24 09:24 UTC by g0pher
Glossary
[[Glossary| Glossary]]\\ see also [[AwkOnWindows| AwkOnWindows]] and [[FIXES| FIXES]] and [[AwkOnWindowsHowto| . . . Dirty Harry: 'you have to be asking yourself- did he fire six awks or only five?' bwk: (Brian . . . standardized, there are enough dark corners .... this is not a good long-term solution.' 'in . . . 'Dark corners are basically fractal — no matter how much you illuminate, . . . is entered.' B1.3 p.245 'White space characters are blank, tab, newline, carriage return, vertical . . .
2K - last updated 2010-10-24 08:14 UTC by g0pher
hashbang
== A script can be treated as an executable file by using a hashbang == It is possible for an awk script . . . file by including a hashbang line as the first line of the script. === The hashbang needs a switch . . .
1K - last updated 2010-11-28 19:04 UTC by markhobley
Hello World in awk
This example program outputs the words "hello world" to the terminal: {{{ awk # Hello World BEGIN { print . . . the [[hash]] symbol and any other characters that follow it until the end of the line: {{{ awk . . . contains. === The print statement The first [[statement]] within the [[main]] function calls . . .
2K - last updated 2010-11-11 19:16 UTC by markhobley
HomePage
This wiki is maintained by regulars from the **#awk** channel on **[[https://libera.chat/|irc.libera.chat]]** . . . up to date, list of some of the ChannelRegulars == Documentation * the traditional [[Frequently . . . Asked Questions]] and their answers * [[XMLScraping]] ok, you don't want to use a parser . . . the difference of two text strings * PrimeNumberSieve implemented in two slightly different ways, . . . with comparative performance numbers under a variety of implementations * ComparingTwoFiles . . .
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]]** . . . つのテキスト文字列の間の差の数を数えるレーベンシュタイン距離]] * [[PrimeNumberSieve|実装の違いによる比較ができるように 2 つの少し異なる方法で実装した素数]] * [[ComparingTwoFiles|2 . . . のフィルタリング問題]] * 解決済み問題 ** rawtaz の [[TCPDumpParser|TCP ダンプ解析]]、これは {{{DoS}}} 攻撃の間に IP をフィルターするのに使います . . . ** Thanatermesis の [[LshalOutputParser|lshal 出力解析]]、これは lshal ユーティリティによる全てのストレージデバイスを見つけるのに使います . . . * inv_arp * karolisl * mike (of the many underbars) * paul * pgas * pr3d4t0r * prince_jammys * redondos . . .
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 . . . post to comp.lang.awk; this allows others to confirm or deny the behavior, and its incorrectness . . . Do not JUST post in comp.lang.awk; Arnold's readership there is sporadic, and of course any Usenet article . . .
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 . . . post to comp.lang.awk; this allows others to confirm or deny the behavior, and its incorrectness . . . Do not JUST post in comp.lang.awk; Arnold's readership there is sporadic, and of course any Usenet article . . .
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 . . . conditional construct. The code within the first block gets executed if the condition is true, otherwise . . .
2K - last updated 2011-09-11 21:43 UTC by 92.40.253.171.threembb.co.uk
index
== Usage == === index [ STRING, SUBSTRING ] === The index [[function]] is used to locate the first occurrence . . .
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]]**. . . . Cuándo usar awk * [[CuandoUsarAwk]] == ¿Cuál versión de awk debería elegir? * [[CualVersionDeAwkDeberiaElegir]] . . . * [[ExpresionesRegulares]] == Conversiones de programas para funcionar en diferentes versiones . . . 2000-2001 by Daniel (not Arnold) Robbins (the first article was recently updated, which is probably . . . gawk's networking facilities (though Plan 9 users are [http://lambda-the-ultimate.org/node/1186|liable . . .
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 . . . the total number of records processed | [[RS]] | A control variable that specifies the input . . .
2K - last updated 2011-05-19 22:40 UTC by markhobley
Invoking an awk program
=== Throwaway one-liners It is often useful to type a simple program at the command line for use within . . .
1K - last updated 2008-12-31 11:34 UTC by pgas
LargestAccurateNumber
Most [[awk]] implementations use floating point double precision to represent every kind of numeric value. . . . worry when one is trying to sum up large numbers in very large log files: when is it safe to rely . . . on awk's numbers and when should one shell out to dc or bc for arbitrary . . . }}} This will print out a list of numbers. The largest reliable value that this process finds . . . exponent=1 with a double precision IEEE 754 numbers. === Technical mumbo-jumbo === IEEE 754 double precision . . .
3K - last updated 2013-04-12 14:52 UTC by ttmrichter
LastField
awk performs a number of actions automatically when it parses lines: it updates the variable NF, which . . . the number of fields on a line; and it parses the record into a series of fields which are accessible . . . that tells awk you want to reference the first field. They behave a bit like an array ie where . . . 1 by an expression, thus $(10-9) also refers to first field. Since the variable NF contains the . . . this whole faq {{{ awk print $1 # prints the first field print $(10-9) # again the first field i=1;print . . .
2K - last updated 2009-02-05 22:43 UTC by firebush.stsci.edu
LastMatchOnLine
The function 'match' sets RSTART to the index of each match and RLENGTH to its length, and returns 0 . . . { while(match(line, re)) { result = substr(line, RSTART, RLENGTH) line = substr(line, RSTART+RLENGTH) . . .
1K - last updated 2009-04-14 22:07 UTC by 216.162.199.202
length
== Usage == === length ([ STRING ]) === The **length** function returns the number of characters within . . . } }}} === Parentheses === In traditional versions of awk, the optional [[parentheses]] enclosures . . .
1K - last updated 2011-06-25 05:11 UTC by pgas
LevenshteinEditDistance
The [http://en.wikipedia.org/wiki/Levenshtein_distance|Levenshtein edit distance] calculation is useful . . . the lazy code could perhaps be modeled via recursion by executing from the end of the string rather . . . implementation. There were eleven previous versions, all of which were benchmarked across gawk, . . . implementation and explored table-based, recursive (with no, single and shared memoization) and . . . lazy models. As expected, the lazy version was incredibly fiddly and not pleasant to read . . .
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]]. . . . extensions (both in the lib and executable version) ** dynamic function calls (call functions by . . .
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 . . . This is not allowed by [[posix]], and some versions of [[awk]] may reject this. === Programs containing . . .
1K - last updated 2009-04-20 15:50 UTC by Mark Hobley
line orientated
== The awk extraction and reporting language is line orientated == The [[awk]] extraction and reporting . . . $1 } }}} Note that line continuation characters must be appropriately placed within a [[rule]]. . . .
1K - last updated 2011-05-17 23:24 UTC by markhobley
LinksPage
<toc> ---- == websites dedicated to awk == * [[http://awk.info/|awk.info]] news and articles about . . . gawk's networking facilities (though Plan 9 users are [http://lambda-the-ultimate.org/node/1186|liable . . . to sniff] that their OS offers a proper /net entry in the filesystem, making such . . . == xml == * [[http://home.vrweb.de/~juergen.kahrs/gawk/XML/| xmlgawk]] * [[http://home.vrweb.de/~juergen.kahrs/gawk/XML/xmlgawk.html#Reading-XML-Data-with-POSIX-AWK . . . | parsing xml with posix awk]] == Articles == * [[http://groups.google.com/group/comp.lang.awk/msg/66b5bf127ae4d443? . . .
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 . . . PasteBin services * http://pastebin.bash-hackers.org - looks like a standard installation of the . . . likely developed and maintained by the same person and/or organization. Or one might just point to . . .
2K - last updated 2015-09-08 09:08 UTC by pgas
literal characters
== Special characters cannot be directly included in a literal string == Special characters, such as . . . can be inserted as literal characters by using literal character notation. == Literal . . . === The following table shows literal characters that can be represented using the backslash, together . . . === Using a backslash to insert literal characters into a string === The following example shows how . . . symbol is used to insert literal characters into a string. Note that the \n digraph is used . . .
2K - last updated 2010-11-28 19:14 UTC by markhobley
logical operator
In [[awk]], *logical operators* are used to perform [[boolean]] operations, and a return a value of [true] . . . *Symbol* | *Description* | [[and]] | [[doubleampersand &&]] | Returns [true] if both [[operand]]s . . . of Logical Operations]] The [[logical]] operators return a [[boolean]] value of 0 for [[false]], and . . . treated as false) print ("apples" && "pears") # 1 (true) print (0 || 7) # 1 (true) print (7 . . . are treated as false) print ("apples" || "pears") # 1 (true) }}} == Precedence * [[Precedence of . . .
3K - last updated 2009-01-02 11:13 UTC by pgas
LshalOutputParser
=== Problem Specification 10:50 <Thanatermesis> i want to obtain the model of the disk, for example, . . . # clear the type annotations as well parseBlockLine() } function parseBlockLine( key, val, . . . the line if (RLENGTH > 0) { type = substr($2, RSTART+1, RLENGTH-2) # offsets to remove parentheses . . . } ########################################## # parser code below ########################################## . . . startBlock() next } /^ / && inBlock { parseBlockLine() next } /^$/ && inBlock { inBlock . . .
3K - last updated 2008-06-27 16:22 UTC by gnomon
main
== Making the application start up from a main routine == In some languages, a '''main''' function provides . . . a program entry point, providing the first user written operations to be performed when the . . .
1K - last updated 2011-07-18 09:57 UTC by markhobley
mawk
The **mawk** package provides a very fast awk implementation by Mike Brennan[1] based on a byte code . . . [1] Brennan still maintains his own version of **mawk** called **mawk-2** which differs from . . . the current version developed by Dickey; it can be found at https://github.com/mikebrennan000/mawk-2 . . .
1K - last updated 2023-11-23 19:50 UTC by AwkwardCoder
mawk wish list
[[mawk_wish_list]]\\ mawk 1.3.4 from Thomas Dickey http://invisible-island.net/mawk/\\ his mawk is even . . . he has added POSIX character classes;\\ WHINY_USERS sorted-array feature;\\ nextfile; "/dev/stdin" name . . .
2K - last updated 2013-05-28 04:04 UTC by g0ph3r
modulus
The [[dyadic]] modulus [[operator]], represented by a [[percent]] sign is used to return the remainder . . . remainder of 15 divided by 4) == Negative Numbers == The modulus operator may be used with negative . . . numbers: print -13 % 7 # -6 == Modulus Combination Assignment . . .
1K - last updated 2011-06-07 00:41 UTC by markhobley
MultipleFiles
<toc> === Version warning Some of these techniques will require non-ancient versions of awk. === . . . Edit this answer]] === How can I treat the first file specially? <include "FirstFile"> [[http://awk.freeshell.org/?action=edit;id=FirstFile| . . .
2K - last updated 2008-11-18 13:38 UTC by pgas
Newline
"print" prints a newline by default. If you don't want a newline, you can use printf instead it is straightforward, . . . you want to join the lines with another characters you can do something like: {{{ sh awk '{printf "%s%s",separator,$0;separator="|"}END{printf . . . truth, in fact print adds the character in ORS, so you can also change ORS to "remove" the newlines . . . {{{ sh printf "%s\n" foo bar | awk -v ORS="|" '{print $0}' }}} The "drawback" of this method . . . is that a trailing ORS is always added. . . .
1K - last updated 2011-07-05 10:53 UTC by pgas
NF
= Number of Fields = The [[special variable]] NF holds the number of [[field]]s in the [[current record]]. . . . record]]. The following [[script]] outputs the first and last [[field]] from each [[record]]: {{{ awk . . .
1K - last updated 2011-05-28 15:14 UTC by markhobley
nudge operator
The *nudge operators* can be used to [[increment]] or [[decrement]] the value of their [[operand]]s, . . . number-- # decrement }}} == Nudge operators can exhibit pre-nudge or post-nudge behaviour The . . . nudge operators can exhibit pre-nudge or post-nudge behaviour, depending . . . against floating point values, the nudge operators will attempt to add or subtract one to obtain a . . . values within an expression, so the nudge operators will return appropriate results: {{{ number = "1" . . .
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 . . . or as [[floating point]] values. == _Numbers should be specified in decimal_ The [[awk]] programming . . . does not provide facilities for specifying numbers in non [[decimal]] bases. However numerical values . . . [[hexadecimal]]. == _Positive and negative numbers_ Negative numbers in awk must be prefixed with a . . . minus numbersign operator: number = -5 It is also possible to . . .
1K - last updated 2011-03-06 22:33 UTC by markhobley
number sign operators
== _Number sign operators_ === _Negative numbers_ The *minus symbol* may be used as a [[unary]] operator . . . number = -5 # -5 is negative === _Positive numbers_ The *plus symbol* may be used as a [unary] operator . . . form is generally not required, because numbers are [[positive]] by default: number = +6 # 6 is . . .
1K - last updated 2011-02-28 12:39 UTC by pgas
numeric strings
Numeric strings obtained from the input source, will be treated as numeric values, when compared with . . . enclosures will be treated as strings of characters and compared lexically. The behaviour of the operators . . . if (a > b) { print "Comparison C: > The first value comes after the second" } if (a < b) { . . . print "Comparison D: < The first value comes before the second" } if (a >= b) . . . { print "Comparison E: >= The first value does not comes before the second" } if (a . . .
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 . . . near line 1 }}} ==== inexplicable parameter parsing (here thinks "<bar>" is arg to sprintf()): . . .
5K - last updated 2012-01-24 08:29 UTC by pgas
operator
The [[awk]] programming language provides a series of *operators* that allow [[value]]s and [[variable]]s . . . compared, evaluated or manipulated. These operators can combined together with [[value]]s and [[variable]]s . . . to make [[expression]]s. The operators may take [[unary]], [[dyadic]] or [[ternary]] form, . . . by the left [[operand]]. == arithmetic operators * [[arithmetic]] operators The [[awk]] programming . . . provides a standard set of [[arithmetic]] operators for manipulating [[integer]] and [[floating point]] . . .
3K - last updated 2011-05-24 22:19 UTC by markhobley
output
== output == === standard output === === output to files === The [[awk]] programming language uses a . . . file is achieved by using [[redirection]] operators. Once [[redirection]] has been defined, the output . . .
1K - last updated 2010-11-16 00:44 UTC by markhobley
Overview
= Overview of awk = == The primarily purpose of awk is to processing textual data to produce formatted . . . [[awk]] has completed its comparisons for the first line of the [[input file]], the cycle is repeated . . . the [[http://markhobley.yi.org/programming/hammers/index.html|hammer scale]], and is classified as . . . of the [[pattern]]s in the order that they first appear within the [[program]]. It is possible for . . .
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 . . . set]]s used to match one or more characters in a single position. * [[modifier]]s used to specify . . . extraction and reporting language uses superset of the [[syntax]] called [[extended regular expression . . .
2K - last updated 2011-05-17 20:32 UTC by markhobley
PassingAShellVariable
The common solution is to use the -v option to define an awk variable giving it the value of the shell . . . are only intrepreted once within / /. {{{ sh #version using a constant awk '/foo\./{print}' #version . . .
1K - last updated 2009-01-30 08:36 UTC by pgas
PassingVariablesToTheParentProcess
How can I put values into the environment of the program that called my awk program? Short answer, you . . . write the results in a form the shell can parse to a temporary file, and have the shell "source" . . . you can use `eval', but this is also cumbersome: {{{ eval `awk 'BEGIN { print "NEWVAR=" somevalue . . .
1K - last updated 2008-11-19 07:45 UTC by pgas
PassingVariablesToTheParentProcessJapanese
How can I put values into the environment of the program that called my awk program? Short answer, you . . . write the results in a form the shell can parse to a temporary file, and have the shell "source" . . . you can use `eval', but this is also cumbersome: {{{ eval `awk 'BEGIN { print "NEWVAR=" somevalue . . .
1K - last updated 2008-11-24 08:05 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 . . . sino que también simplifica el control de versiones, y permite reconstruir casos de prueba con . . .
1K - last updated 2009-01-03 03:02 UTC by fcr
PasteBin
A PasteBin is a site that allows one to paste chunks of code or text. The snippet is given a unique URL . . . directly into IRC to avoid interrupting conversation, to facilitate versioning, and to make it easy . . .
1K - last updated 2015-09-08 09:07 UTC by pgas
pattern
In [[awk]], patterns are used to select lines of input for processing. The pattern within each [[rule]] . . . records ==== Note that [[foo]] selects the first matching [[record]], [[bar]] must be in a later . . .
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 . . . with the highest priority are evaluated first. An [[neophite|inexperienced programmer]] may expect . . . than [[addition]], so it is performed first. {{{ print 3 + 4 * 5 # This produces 23 because . . . so their contents are evaluated first: {{{ print (3 + 4) * 5 # The parentheses cause . . . the multiplication }}} == _Groups of operators or functions within parentheses have the same precedence . . .
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 . . . on all keys that index into arrays (integers are converted to strings and then hashed; all array . . . marked as //1// completed too fast to yield numbers large enough to be distinguishable from timing error. . . . across multiple implementations. These numbers are only useful for relative comparison. Tests were . . .
4K - last updated 2008-06-19 05:56 UTC by gnomon
PrintASingleQuote
This question gets asked often enough that it deserves its own answer. This common question doesn't actually . . . ...the shell complains, because it tries to parse "Hello, World!" as a string of commands to be inserted . . . between two singlequoted strings. The first thought one might have is to surround the program . . . obvious solution - using hex-escaped characters - seems to work at first: {{{ awk 'BEGIN{print "it . . . dependent. ==== Octal Escapes: Great Personality, but... Fortunately we can always regress . . .
5K - last updated 2015-07-05 09:45 UTC by pitman
printf
== Usage == === printf [ FORMAT, LIST ] === The **printf** [[variadic]] function provides generic [[string . . . %f, %g, %G, %i, %o, %s, %u, %x, %X and %% [[conversion specifier]]s, and the h and l [[conversion qualifier]]s. . . . ", $i;print ""}' filename }}} Do NOT print the first word on each line: {{{ awk '{for(i=2;i<=NF;++i) . . . "%s ", $i;print "" }' filename }}} Print the first to the eighth word on each line: {{{ awk '{ i=0; . . . $i }' filename }}} Delete all newline characters in a file: {{{ awk '{printf "%s ",$O}' filename . . .
2K - last updated 2011-06-09 20:34 UTC by markhobley
PrintingNumbers
Use printf and a format string instead of print, some examples: {{{ awk BEGIN { printf "%f", 1000001.10 . . . awk manual]] But why does this happen in the first place? awk does something like printf using the . . . # here it is printed as a string without conversion 12.1231 # same as printf "%.6g",$1 ($1+0 is a . . . see [[truth]] There is also another conversion that happens when a number is transformed into . . . a string but not by print, this conversion is controlled by CONVFMT, which is also "%.6g" . . .
2K - last updated 2009-03-04 12:34 UTC by pgas
PureEvil
Not related to awk, just for fun. Some deliberately obfuscated and evil commands: {{{ sh # squeeze the . . . shell printf "%s\n" foo '' '' bar | awk $$${$+ RS=} #another version, requires bash, ksh or zsh awk . . . {newlines,RS}={12,} #not useful at all...in bash function for . . . bar foo" | sed ':;;\;foo;s;;;;t;' #cut the first field a string separated by : (like cut -d: -f1) . . .
1K - last updated 2011-09-08 14:00 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| . . . * calling a function with or without parameters and getting its return value. * customizing I/O . . . handlers for file, pipe, console I/O. * creating multiple . . . interpreters independent of each other. * running a single script . . . following steps: * open a new interpreter * parse in a source script * open a new runtime context . . .
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 . . . shift $1=$3 $2=$4 ... NF=8-3+1 # only keep the first six fields print }}} ==== Drawbacks of using a . . . ":""), $i}; printf "\n"}' file # uses OFS and ORS awk '{for (i=2; i<=NF; i++) printf("%s%s", $i, . . . i==NF ? ORS : OFS)}' file }}} A loop to select individual fields . . . will also cause anything that appears between the fields to be replaced with " ". This . . .
10K - last updated 2015-09-08 09:52 UTC by pgas
ReadDirectory
Getting a list of files in a directory is a tricky process. One might be tempted to try use ls and getline, . . . but as we know [[http://mywiki.wooledge.org/ParsingLs|parsing ls is a bad idea]]. A file name can . . . cannot contain null (undefined behavior) and RS can only be a single character. This leaves us with . . . the only reasonable separator. {{{ awk BEGIN { RS = "/" cmd = "cd \""dir"\" && printf '%s/' . . . storing the files to get a fuller path. In gawk, RS can be a regex and can contain null. This makes . . .
2K - last updated 2013-10-03 22:35 UTC by emg
record
The awk utility divides its [[input]] into records and [[field]]s. == By default, each line of input . . . are actually separated according to the [[RS|record separator]] character. This has a default . . . separator == By changing the value of the [[RS|record separator]], it is possible to change the . . .
1K - last updated 2011-05-17 23:52 UTC by markhobley
Recursively Include C headers
=== Problem Specification i want to generate one big .hpp file out of multiple .hpp files and want to . . . the text of all #include "foo.hpp" file recursively === Code {{{ awk #!/usr/bin/awk -f # by goedel . . . \t]*#include[ \ ]*"[^"]+"/)) { f = substr(line, RSTART, RLENGTH) sub(/^[ \t]*#include[ \t]*"/, "", . . .
1K - last updated 2011-12-11 05:33 UTC by pgas
regular expression operator
The [[awk]] programming language provides a set of *regular expression operators* that have special meanings . . . == _Regular Expression Binding Operators_ The *regular expression binding operator* applies . . . cannot be performed with binding operators_ Note that the regular expression binding operators . . . text } }}} == _Basic Regular Expression Operators_ | *Char* | *Name* | *Purpose* | ^ | [[caret]] | . . . a newline == _Extended Regular Expression Operators_ | *Char* | *Name* | *Purpose* | + | [[plus]] | . . .
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 . . . :"") } }}} The function {{{rep}}} above is recursive, but performs very well under mawk, gawk and . . .
1K - last updated 2009-03-01 19:15 UTC by h-67-101-152-180.nycmny83.dynamic.covad.net
reverse
The [[awk]] extraction and reporting language does not provide a [[builtin]] function for reversing strings. . . . example demonstrates the definition of a reverse function and its invocation: {{{ awk function reverse(s) . . . 1) revs = revs c } return revs } # Call the reverse function to reverse our string BEGIN { print reverse("anut . . .
1K - last updated 2011-06-25 05:11 UTC by pgas
ReverseMapping
{{{ awk # reverse mapping of keys -> values in given array function reverse_mapping(array, tmp_key, . . . for (key in array) { # if we already reversed this pair to avoid a collision, continue if (key . . . array[ key] tmp_element = array[tmp_key] } # reverse the mapping of our current key -> element pair . . . delete array[key] # if we had a collision, reverse those values, too if (tmp_key) { array[tmp_element] . . . for (k in a) printf("a[%s] = %s\n", k, a[k]) reverse_mapping(a) printf("\n") for (k in a) printf("a[%s] . . .
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 . . . the record separator to an exclamation mark RS = "!" } }}} The -v command line switch enables the . . . be considered when passing command line parameters this way. == Changing the record separator in the . . . Road London Bobby Lewis 48 Dockside Row Merseyside }}} Note that blank lines must be completely . . .
3K - last updated 2013-02-19 23:11 UTC by markhobley
SedFAQ
<toc> ---- == I have a line like "abdcgfjeuPATTERNfjfhghj", I want to get the PATTERN part, why . . . that produces an equivalent result, and of course it does not work. It just replaces, within the . . . end of the string, and between any two characters in the string (if it cannot match a longer string, . . . of course). /b*/ just happens to be one such expression, . . . greedy, but generally they also stop at the first match they are able to find, moving from left to . . .
34K - last updated 2010-02-14 17:56 UTC by waldner
Shellquote
This function ensures that strings you use as arguments to the **system()** function (or **"cmd"{{{|}}}getline** . . . commands) are safely quoted. First, all single quotes are converted to '\'', and finally, . . .
1K - last updated 2009-03-01 00:35 UTC by h-67-101-152-180.nycmny83.dynamic.covad.net
ShellQuoting
Quoting can be such a headache for the novice, in shell programming, and especially in awk. Art Povelones . . . is probably the best, and easiest to understand and maintain, for most purposes: (the '@@' is . . . (see below for a verbose explanation of the first one, with 7 quotes) awk 'BEGIN { q="'"'"'";print . . .
2K - last updated 2008-11-19 07:41 UTC by pgas
SimpleCalc
Simple 4 operations calculator ... {{{ awk # usage: print calc("5 * (1 + 2) * 5 + 7") # reads and update . . . s[0] # return the first token function next_token(s, t) { sub(/^[[:space:]]*/,"", . . . || match(s[0], /^[-+*/]/)) { t = substr(s[0], RSTART, RLENGTH) s[0] = substr(s[0], RLENGTH+1) return . . .
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 . . . writes: {{{ > SunOS includes three versions of awk. /usr/bin/awk is the old > (pre-1989) . . . version. /usr/bin/nawk is the new awk which appeared . . .
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 . . . writes: {{{ > SunOS includes three versions of awk. /usr/bin/awk is the old > (pre-1989) . . . version. /usr/bin/nawk is the new awk which appeared . . .
1K - last updated 2008-11-24 08:36 UTC by pgas
special variable
Some [[variable]] names have a special meaning to the awk interpreter. == List of special variables == . . . | A control variable that specifies the conversion format of numerical strings | [[ENVIRON]] | An . . . that specifies the output field separator | [[ORS]] | A control variable that specifies the output . . . length of the currently matched substring | [[RS]] | A control variable that specifies the input . . . record separator | [[RSTART]] | An informative variable that provides the . . .
2K - last updated 2011-06-25 05:46 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. . . . painful. However, gawk, mawk, and the newest version of the Bell Labs awk all allow you to set FS . . . "" as the third argument of split. So, split("chars",anarray,"") results in the array anarray containing . . .
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. . . . painful. However, gawk, mawk, and the newest version of the Bell Labs awk all allow you to set FS . . . "" as the third argument of split. So, split("chars",anarray,"") results in the array anarray containing . . .
1K - last updated 2008-11-24 08:35 UTC by pgas
statement
The [[awk]] extraction and reporting language is not [[imperative]]. However, [[action]]s within the . . . World!" exit } }}} == Continuation characters can appear anywhere within a statement == In [[awk]], . . .
2K - last updated 2011-05-21 16:43 UTC by markhobley
string
== _Literal strings are delimited using doublequotes_ In [[awk]], literal strings are delimited using . . . notation can be used to include special characters_ It is possible to include [[special character]]s . . .
1K - last updated 2010-10-19 21:58 UTC by markhobley
string manipulation
* [[case conversion]] * [[length|Determine the length of a string]] * [[index|Determine the position . . . within a string]] * [[substr|Removing the first and last characters from a string]] * [[reverse|Reverse . . . * Strip control codes and extended characters from a string * Test for an [[empty string]] * [[transliteration]] . . .
1K - last updated 2011-07-04 22:12 UTC by markhobley
string manipulation function
The [[awk]] programming language provides a set of [[builtin]] functions for performing various string . . . [[sprintf]] * [[sub]] * [[substr]] * [[case conversion|tolower]] * [[case conversion|toupper]] . . .
1K - last updated 2011-06-07 00:35 UTC by markhobley
StupendousSedSwitch
Although not strictly pertinent to the goings on in {{{#awk}}}, there is a significant overlap of those . . . channelgoers in the related channel {{{#sed}}}, and I don't know . . . an admin. Due to Freenode policy, the regulars in {{{#sed}}} cannot really claim that channel name . . . founder nor the network admins. uniplex, BearPerson et al decided that this situation had gone on . . . and a proper list of admins and successors were registered with the chanserv bot. On 2009-09-14, . . .
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; . . . { font-size:smaller; font-style:italic; } div.rss { background-color:#EEF; } div.search { background-color:#F1F5FF . . .
5K - last updated 2008-06-19 16:46 UTC by pgas
substr
=== Removing the first and last characters from a string === The following [[script]] demonstrates how . . . functions can be combined to remove the first and last [[character]]s from a [[string]]: {{{ . . . print substr(mystring,2) # remove the first letter print substr(mystring,1,length(mystring)-1) . . . # remove both the first and last character } }}} . . .
1K - last updated 2011-06-25 05:10 UTC by pgas
symbol
| *Symbol* | *Name* | *Purpose* | !! | [[pling]] | logical NOT | " | [[doublequote]] | | # | [[hash]] . . . anchor | % | [[percent]] | | & | [[ampersand]] | | ' | [[apostrophe]] | | * | [[asterisk]] . . . anchor and compliment box indicator | !_ | [[underscore]] | | ` | [[backtick]] | | | [[pipe]] | regular . . .
2K - last updated 2013-02-19 14:26 UTC by markhobley
text.2.wiki.awk
#: C:\#\awk\lib\text.2.wiki.awk\\ . . . s..v strings; i..n integers; w..z reals\\ {{{ #: regular expression . . . metacharacters: \ ^ $ . [ ] | ( ) * + ? escape with \ }}} \\ {{{ . . .
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 . . . A, B.. arrays; s..v strings; i..n integers; w..z reals #: regular expression metacharacters: . . .
2K - last updated 2012-09-16 09:12 UTC by g0ph3r
tracert.awk
{{{ awk #:: C:\_\_u\tracert.awk #: 2014-07-06 19:47:02 #:: rod.t_2014 #:: extract basename for tracert . . . /([a-z0-9-]+[.])+[a-z0-9-]+/); s = substr(s, RSTART, RLENGTH); s = (_cmd)s; print(" cmd =", (_q)(s)_q); . . . sub(s,n)==1 #: regular expression metachars: \ / ^ $ . [ ] | ( ) * + ? #: filenames may Not . . .
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]], . . . and may even vary depending on which version of awk is being used. ==== Taking zero from the . . . is taken from the data source, then awk considers this to be a numeric value and it evaluates to false . . . source. The example demonstrates that awk considers $1 to be a numeric value and it evaluates to false: . . . ie with nawk, oawk on solaris and netbsd awk version 20050424 {{{ sh nawk 'BEGIN{var="0"; foo=var+0;if . . .
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 . . .
1K - last updated 2008-12-31 09:58 UTC by pgas
UsuariosFrecuentesDelCanal
Lista de usuarios frecuentes en el canal, sin ningún orden en particular: * axisys * gnomon * gnubien . . . * inv_arp * karolisl * mike (of the many underbars) * paul * pgas * pr3d4t0r * prince_jammys * redondos . . .
1K - last updated 2009-02-12 23:10 UTC by fcr
variable-español
AWK no es el shell, y tampoco es Perl. Antes que nada, las variables en AWK se referencian utilizando . . . se coloca $ en frente a las palabras para referirse a estas como una variable - si deseas acceder a . . . con # separador", usando la variable ORS. # Así que asumiendo que ORS es " ", lo siguiente . . .
2K - last updated 2009-01-03 04:02 UTC by fcr
variable
A '''variable''' is a symbolic name associated with a [[value]]. A variable acts as a container and the . . . a sequence of [[letter]]s, [[digit]]s, or [[underscore]] symbols, and may not begin with a [[digit]]. . . . and separate from each other: {{{ # The identifiers dog,Dog and DOG represent separate variables BEGIN . . . is " ", the following is the equivalent to the first example above: {{{ awk print "hello", name; }}} . . .
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**. . . . NOT use the string alone and expect awk to understand that you mean $0 ~ string, as happens instead . . .
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 . . . remarkably good consistency between them * terse domain-specific syntax * rapid execution, fast . . . awk only exposes the results of its field parsing and hides the offsets (but look at the optional . . . the type of a variable: strings and numbers get automatically converted from type to type. This . . . can create mysterious problems because the conversion operation is, in fact, rather slow; and since . . .
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 . . . Most implementations of awk are interpreters which read your awk source program and parse it . . . and act on it directly. Some vendors have developed awk compilers which will produce . . . code. There are also various awk->C converters which allow you to achieve the same functionality . . . C code later). One of the most popular compilers, from Thompson Automation [[http://www.tasoft.com/tawk.html|tawk]], . . .
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 . . . Most implementations of awk are interpreters which read your awk source program and parse it . . . and act on it directly. Some vendors have developed awk compilers which will produce . . . code. There are also various awk->C converters which allow you to achieve the same functionality . . . C code later). One of the most popular compilers, from Thompson Automation, continues to be the subject . . .
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 . . . at the beginning of the block, and don't re-parse just because you changed FS. To get the desired . . . awk { FS=":"; print $1 } }}} on this data: {{{ first:second:third but not last:fourth First:Second:Third . . . But Not Last:Fourth FIRST:SECOND:THIRD BUT NOT LAST:FOURTH }}} you may get . . . either: {{{ this: or this: ---- ------- first first:second:third First First FIRST FIRST }}} . . .
1K - last updated 2008-12-15 12:46 UTC by pgas
Which version of awk should I choose
This is a comparison between the original [awk] package and other variants. | | [[awk]] | [[bwk]] | [[gawk]] . . .
1K - last updated 2011-08-13 20:50 UTC by 92.40.253.96.threembb.co.uk
WhichIsBetter
This comes up so often that it deserves a page on its own. **NEVER**, **EVER** ask computer people whether . . . is **the best**", which will really annoy the person you are asking. People sometimes seem to think . . . read on to find out how to get better answers. The single most important thing to keep in mind . . . * compliant (to some specification) * understandable * works with your hardware * supported by . . . further clarification if occurring in a conversation, even (or especially) between geeks. So you . . .
5K - last updated 2009-07-12 09:13 UTC by host-87-74-84-72.dslgb.com
whitespace
== _Line breaks are best placed at whitespace points_ The [[awk]] extraction and reporting language is . . . This means that [[newline]] characters cannot be used to create a line break at arbitary . . .
1K - last updated 2011-03-20 22:07 UTC by markhobley
XMLScraping
You cannot easily parse xml with awk. But there are several tricks to scrap an xml file: <toc> . . . {{{ field1 FS field2 FS field3 }}} where the first FS is the opening tag and the second one is the . . . containing the attribute name: {{{ sh awk -v RS='"' '/foo=$/{getline;print}' }}} * another possibility, . . . that we have one tag per record. {{{ sh awk -v RS=\> -F '<tag.*foo="' 'NF>1{sub(/".*/,"",$2);print . . .
2K - last updated 2011-11-23 15:06 UTC by pgas
y0tta
**y0tta:** http://awk.freeshell.org/y0tta revised: 2014-05-30 . . . Harry: ''you have to be asking yourself -\\ did he fire six awks . . . FMS/CTSS MVS RSX11M un1x:6/7 bsd:4 . . .
3K - last updated 2014-05-30 05:06 UTC by g0ph3r
177 pages found.
