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Adler32Checksum
As documented in the [[http://en.wikipedia.org/wiki/Adler-32 | Adler-32 Wikipedia article]]. {{{ awk . . . not laziness, it's constructive efficiency. } BEGIN {printf "'%X' should match '%s'\n", adler32("Wikipedia"), . . .
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 . . . several different ways and should not be used by beginners. ... come back and study the getline command . . . it: **a)** Normally FILENAME is not set within a BEGIN section, but a non-redirected call to getline . . . file1 file2 a }}} h) Using getline in the BEGIN section to skip lines makes your program difficult . . . line 10000 }}} you may consider using... {{{ awk BEGIN { getline header; getline } { whatever_using_header_and_data_on_the_line() . . .
16K - last updated 2009-02-15 22:14 UTC by waldner
ArrayLength
Posix does not define a way to get the length of an array, while you could use a loop to count the elements . . . the length of array is %d\n", length(array) } BEGIN{ array[1]="foo";array[2]="bar" printf "the length . . .
2K - last updated 2009-02-09 09:45 UTC by arnold.robbins
awk benchmarks
post awk benchmarks here:\\ see http://awk.freeshell.org/awk.exe for awks used here.\\ {{{awk C:\#> . . . tt %mawk% -v n=5e4 -v s=x BEGIN{n+=0;for(i=1;i!=2048;i*=2)s=(s)(s);print( ARGV[0],n,i,length(s));while(n--)m=split(s,A,N);print(m,length(N))} . . . }}} {{{awk C:\#> tt %gawk% -v n=4e3 -v s=x BEGIN{n+=0;for(i=1;i!=2048;i*=2)s=(s)(s);print( ARGV[0],n,i,length(s));while(n--)m=split(s,A,N);print(m,length(N))} . . .
1K - last updated 2012-08-26 14:21 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) . . . }}} array SYMTAB holds info, eg: {{{awk BEGIN { _print_SYMTAB(); exit(0); } function _print_SYMTAB( . . .
2K - last updated 2012-03-18 23:21 UTC by g0pher
AwkDc
This is an awk implementation of the [http://www.gnu.org/software/bc/manual/dc-1.05/html_mono/dc.html|dc] . . . test cases: === The test suite {{{ BEGIN { SP = "SP" #S[SP] = -1 test1() test2() test3() . . .
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 . . . # 4}}}| |=-v to pass values|{{{awk -v foo=bar 'BEGIN {print foo}' # bar}}} | |=ENVIRON array|{{{a=FOO . . . awk 'BEGIN {print ENVIRON["a"]}' # FOO}}}| |=gensub()|{{{echo . . . # aboa}}}| |=strftime()|{{{awk 'BEGIN{print strftime("%F %T",1)}' # 1970-01-01 00:00:01}}}| . . . |=length(array)|{{{awk 'BEGIN{a[1]=10;a[2]=20;print length(a)}' # 2}}}| |=asort()|{{{awk . . .
4K - last updated 2015-04-27 13:23 UTC by pgas
AwkGuide
** Work in Progress ** {{{ import from Mark Hobley's wiki }}} <toc> ---- == Overview * [[Overview]] . . . * [[associative container]]s * [[backslash]] * [[BEGIN]] * [[bitwise operator]]s * [[block]]s * [[brace]]s . . .
4K - last updated 2011-08-14 15:57 UTC by markhobley
AwkOnWindowsHowto
AwkOnWindowsHowto\\ rough cut - needs edit {{{ 3) awk command line switches/usage from a win32 cmd.exe . . . undocumented -d does debug dump examples: awk95 "BEGIN {print \"Hello, World!\"}" |- Hello, World! #: . . . output of above awk95 -v s="Hello, World!" BEGIN{print(s)} |- Hello, World! #: pgm needs no " . . . since no spaces awk95 -v s=Hello,\040World! BEGIN{print(s)} |- Hello, World! #: \040 is octal for . . . space echo BEGIN {print "Hello, World!"} | awk95 -f - |- Hello, . . .
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 . . . range expressions, like {{{ # prints lines from /beginpat/ to /endpat/, inclusive awk '/beginpat/,/endpat/' . . . A way is to use these: {{{ # prints lines from /beginpat/ to /endpat/, not inclusive awk '/beginpat/,/endpat/{if . . . (!/beginpat/&&!/endpat/)print}' # prints lines . . . from /beginpat/ to /endpat/, not including /beginpat/ awk . . .
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, . . . is far more regular (another advantage for the beginner, even without considering syntax-highlighting . . .
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, . . . is far more regular (another advantage for the beginner, even without considering syntax-highlighting . . .
2K - last updated 2008-11-24 08:05 UTC by pgas
BEGIN
== Begin Blocks The [[awk]] programming language allows us to use **begin blocks** and **end blocks** . . . actions within the program. == Execution **Begin blocks** act as [[constructor]]s and are executed . . . only before the first [[input]] record is read. Begin blocks are prefixed with the BEGIN keyword and . . . There is no default action provided for begin block, so they must contain explicit actions. . . . **Begin blocks** are typically used to initialize [[variable]]s, . . .
3K - last updated 2013-04-11 14:25 UTC by 92.40.253.171.threembb.co.uk
case conversion
The [[awk]] extraction and reporting language provides the toupper and tolower functions for converting . . . the provided argument remains unchanged: {{{ awk BEGIN { mystring = "I Like Apples" print (tolower(mystring)) . . . the provided argument remains unchanged: {{{ awk BEGIN { mystring = "I Like AppLes" print (toupper(mystring)) . . .
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 . . . dog,Dog and DOG represent separate variables BEGIN { dog = "Benjamin" Dog = "Samba" DOG = "Bernie" . . .
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 (tolower(avar)=="a") { ... } }}} Or at the beginning of your code, add a line like: {{{ awk { . . .
1K - last updated 2008-11-26 12:39 UTC by pgas
command line parameter
The [[awk]] extraction and reporting language uses traditional conventions for accessing command line . . . variable ARGC. {{{ awk #!/usr/bin/awk -f BEGIN { print "There are " ARGC "command line parameters" . . .
1K - last updated 2011-06-25 05:49 UTC by pgas
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/ . . . Edit this answer]] ---- == Why does awk 'BEGIN { print 6 " " -22 }' lose the space? <include . . .
8K - last updated 2009-03-04 12:42 UTC by pgas
comparative operator
The comparative operators are used to determine equality or inequality or otherwise make comparisons . . . for equivalence and lexical ordering: {{{ BEGIN { a="BALL" b="BELL" if (a == b) { print "The . . . an expression: {{{ # This script contains a bug BEGIN { n=2 IF (n=3) PRINT "n is equal to 3" # The . . .
3K - last updated 2013-02-24 17:38 UTC by markhobley
concatenation
== The awk programming language does not have an explicit concatenation operator == The awk programming . . . is allowed between the [[value]]s: {{{ awk BEGIN { name = "Bob" print "Hello " name } }}} === . . . between them: {{{ awk # This will output 234 BEGIN { print 2 3 4 } }}} === Precedence === Note that . . . {{{ awk # This will not produce a result of 358 BEGIN { print 2 3 4 + 1 2 3 # This actually produces . . .
1K - last updated 2011-06-25 05:13 UTC by pgas
continuation
Line continuation enables long lines of code to split across several lines for the purpose of making . . . to be split across several lines: {{{ BEGIN { # The backslash symbol can be used to spread . . .
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]] . . . if(sign) fval=fval*-1 return fval } BEGIN { } { print HexToFP($4, $3, $2, $1) # for use . . . number if(sign != 0) fval *= -1 return fval } BEGIN { x = f_ieee754(0x41f24000) printf("x = %f\n",x) . . .
3K - last updated 2010-06-23 19:49 UTC by john b
division
== Quotient Division == The [[slash]] symbol can be used as the division [[operator]] to produce the . . . results from a mathematical quotient: BEGIN { print int(22 / 6) } == Division by zero == . . . a fatal error in traditional awk implementations BEGIN { print 3 / 0 # inf } . . .
2K - last updated 2011-03-20 07:07 UTC by markhobley
END
The [[awk]] programming language allows us to use **end blocks** to provide [[finishoff]] and [[cleanup]] . . . with the **END** label: {{{ END { # This is a begin block print "The end is here" # Print the closing . . .
2K - last updated 2011-04-30 22:52 UTC by markhobley
enumeration
The [[awk]] extraction and reporting language does not directly support enumeration. However, it is possible . . . the values for a set of fruit names: {{{ BEGIN { n=1 # We are enumerating from a value of one . . .
1K - last updated 2011-05-27 15:28 UTC by markhobley
environment
The ENVIRON [[associative container]] contains the values of the current environment. This enables an . . . name as [[key]] within the container: {{{ BEGIN { print "Your home directory is "ENVIRON["HOME"] . . .
1K - last updated 2011-06-07 01:05 UTC by markhobley
EnvVarGeneral
**Answer 1:** On Unix, use "alternate quoting", e.g. {{{ awk -F: '$1 ~ /'"$USER"'/ {print $5}' /etc/passwd . . . on comp.lang.awk): {{{ $ var="#" $ awk 'BEGIN{ print '"$var"' }' awk: cmd. line:1: BEGIN{ print . . . quotes in the awk program: {{{ $ var="#" $ awk 'BEGIN{ print "'"$var"'" }' # }}} However, there are . . . is not enough: {{{ $ var="hello world" $ awk 'BEGIN{ print "'"$var"'" }' awk: BEGIN{ print "hello . . . -v: {{{ $ var="hello world" $ awk -v var="$var" 'BEGIN{ print var }' hello world }}} See next answer . . .
3K - last updated 2011-07-05 09:31 UTC by pgas
EnvVarGeneralJapanese
== 環境変数を使う **解答 1:** Unix では「もうひとつのクォート」を使います。例えば、以下のようなものです。 {{{ awk -F: '$1 ~ /'"$USER"'/ {print $5}' . . . で議論されている) いくつかの例を上げておきます。 {{{ $ var="#" $ awk 'BEGIN{ print '"$var"' }' awk: cmd. line:1: BEGIN{ print . . . {{{ $ var="#" $ awk 'BEGIN{ print "'"$var"'" }' # }}} しかしながら、これで十分というわけではありません。 . . . {{{ $ var="hello world" $ awk 'BEGIN{ print "'"$var"'" }' awk: BEGIN{ print "hello . . . {{{ $ var="hello world" $ awk -v var="$var" 'BEGIN{ print var }' hello world }}} 次に -v を使った解答を見ていきましょう。 . . .
2K - last updated 2008-11-23 14:37 UTC by hi saito
escape sequence
Some characters cannot be included in [[literal string]]s, because they are [[nonprintable]] or [[control . . . symbol is used to [[delimit]] the beginning or end of a string. This means that a [[doublequote]] . . . the [[backslash]] symbol is used to mark the beginning of an escape sequence. In order to represent . . .
3K - last updated 2008-12-30 13:07 UTC by Mark Hobley
ExitCode
Normally, the `exit' command exits with a value of zero. You can supply an optional numeric value to . . . you may have to do something like this: {{{ awk BEGIN \ { exitcode=0; ... } # normal rules processing... . . .
1K - last updated 2008-11-26 12:30 UTC by pgas
FileAndBitJoinClone
== Problem Description This was difficult to hash out. Eventually the task was described as, "for each . . . quite easy. == The Code {{{ #!/usr/bin/awk -f BEGIN { BIT = "bit.txt" FILE = "file.txt" ERRSTR = . . . {{{| sed -ne '/^begin-base64/,/^====$/p'}}} {{{| uudecode -o-}}} {{{| . . . and 'bit.txt' in the current directory. {{{ begin-base64 644 ajai-files.tar.gz H4sICIbrakgCA2FqYWktZmlsZXMudGFyAO2aa67cyLGE9Xe0it7AEJWZ9VyO . . .
7K - last updated 2009-03-08 16:26 UTC by waldner
FindAllIndices
Sometimes it is useful to find the index of every occurrence of a given character in a string. Let's . . . ones. Each odd-numbered index indicates the beginning of a doublequoted string and each even index, . . .
2K - last updated 2011-07-05 10:53 UTC by pgas
FirstFile
you can tell if awk is parsing the first file given on the command line using FILENAME, thusly: {{{ awk . . . BEGIN { rulesfile="" } rulesfile == "" { rulesfile . . . replacing some old lines with new lines. {{{ awk BEGIN { rulesfile="" } rulesfile == "" { rulesfile . . .
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 . . . BEGIN { rulesfile="" } rulesfile == "" { rulesfile . . . replacing some old lines with new lines. {{{ awk BEGIN { rulesfile="" } rulesfile == "" { rulesfile . . .
1K - last updated 2008-11-24 08:09 UTC by pgas
FIXES
[[FIXES]] revised: . . . 2014-01-15 23:10 UTC\\ \\ Near the beginning was the 1987 awk book:\\ [[http://cm.bell-labs.com/cm/cs/awkbook/| . . . before the BEGIN block for sure. they have . . . assignment.\\ \\ FILENAME is now defined in the BEGIN block (Oct 11, 1989)\\ "-" means stdin in getline . . .
6K - last updated 2014-01-15 23:17 UTC by g0ph3r
FormatFileSizes
From time to time people ask how to sort the output of {{{du -h}}}. This is not particularly easy, since . . . has been sorted: {{{ du dir | sort -n | \ awk 'BEGIN {u[0]="K";u[1]="M";u[2]="G";} { size=$1;sub(/^[^\t]+\t+/,"");name=$0 . . .
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]] . . . field echo "Rhubarb Custard Bananas" | awk 'BEGIN { FS = " " } { for (l=1;l<=NF;l++) print l . . . fields echo "Rhubarb##Custard##Bananas" | awk 'BEGIN { FS = "#" } { for (l=1;l<=NF;l++) print l . . . fields echo "Rhubarb Custard Bananas" | awk 'BEGIN { FS = "[ ]" } { for (l=1;l<=NF;l++) print . . . #!/bin/sh echo ' Rhubarb Custard Bananas '| awk 'BEGIN { FS = " " } { print $2 }' # This gives Custard . . .
5K - last updated 2013-02-19 21:45 UTC by markhobley
GeneralizedTextReplacement
Some times people need to recode in awk something they were previously doing with sed or another tool. . . . find out what's in orgstr between match i-1 (or beginning of string) and i psep=substr(orgstr,last,start[j]-last) . . .
6K - last updated 2009-03-26 20:38 UTC by waldner
GeoLocation
{{{ awk #!/bin/gawk -f function getcoord(string, a) { split(string, a, ":") gsub(/\"/, "", a[2]) return . . . (in_body) return $0 if (/^\r$/) in_body = 1 } } BEGIN { data = httpget() split(data, coords, /,/) lat . . .
1K - last updated 2011-11-14 16:35 UTC by pgas
Hello World in awk
This example program outputs the words "hello world" to the terminal: {{{ awk # Hello World BEGIN { print . . . # Comments after a hash sign are ignored }}} === Begin Blocks The [[BEGIN]] block is executed once only . . . === Squiggly Brackets The contents of the begin function is enclosed in [[brace]]s. This defines . . .
2K - last updated 2010-11-11 19:16 UTC by markhobley
include
The [[awk]] extraction and reporting language does not support the use of include files. However, it . . . called from the same command line: {{{ # one.awk BEGIN { sayhello() } # two.awk function sayhello() . . .
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 . . . be found, then a value of [[zero]] is returned: BEGIN { print index("Staffordshire","ford") # 5 } === . . .
1K - last updated 2011-06-09 20:36 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 . . . [[argument]] of the [[awk]] command: {{{ sh awk 'BEGIN {print "Hello World!"}' }}} === Running an awk . . . line as follows: {{{ sh #!/usr/bin/awk -f BEGIN { print "Hello World!" } }}} === Using awk as . . .
1K - last updated 2008-12-31 11:34 UTC by pgas
iterative loop
An '''iterative loop''' repeatedly executes a set of instructions as the [iterator] steps through a series . . . and [increment]s on each consecutive [loop]: BEGIN { for (l= 0; l <= 9; l++) { print l } } === . . .
2K - last updated 2011-08-13 21:00 UTC by markhobley
LargestAccurateNumber
Most [[awk]] implementations use floating point double precision to represent every kind of numeric value. . . . N is no longer distinct from N+1: {{{ sh awk 'BEGIN{for (i = 0; i < 64; i++) printf "%s\t%19.0f\t%s\n", . . .
3K - last updated 2013-04-12 14:52 UTC by ttmrichter
length
== Usage == === length ([ STRING ]) === The **length** function returns the number of characters within . . . a provided string [[argument]]: {{{ awk BEGIN { print length("Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch") . . .
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 . . . from the end of the string rather than the beginning. If experiments are run, the results will . . . running an edit distance between them {{{ awk BEGIN {OFS = "\t"} {words[NR] = $0} END { max = 0 for . . . str1, str2, correctval, testval return 0 } } BEGIN { testlevdist("kitten", "sitting", 3) testlevdist("Saturday", . . .
6K - last updated 2010-04-16 10:19 UTC by pgas
limitation
== Limitations of awk Some traditional versions of [[awk]] derived from [[Unix]] version 7, may not conform . . . may reject this. === Programs containing only BEGIN actions may read and discard input It is a requirement . . . of [[posix]] that if a program contains only [[BEGIN]] actions, and contains no instances of [[getline]], . . . device]] to work around this problem: awk 'BEGIN {print "Hello world!"}' </dev/null . . .
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 . . . The [[action]] for each [[rule]] must begin on the same line as the [[pattern]]. However, . . .
1K - last updated 2011-05-17 23:24 UTC by markhobley
literal characters
== Special characters cannot be directly included in a literal string == Special characters, such as . . . by using a [[representation code]] that begins with a [[backslash]] symbol: === Literal Character . . .
2K - last updated 2010-11-28 19:14 UTC by markhobley
LshalOutputParser
=== Problem Specification 10:50 <Thanatermesis> i want to obtain the model of the disk, for example, . . . "block" of this (so, every section) === Code {{{ BEGIN { skip = 1 inBlock = 0 FS = " = " } function . . .
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 . . . function. However, it does support the use of [[begin]] blocks, which can be used to provide us with . . . startup [[block]] for our application: {{{ BEGIN { # This is our main startup procedure print . . .
1K - last updated 2011-07-18 09:57 UTC by markhobley
mawk wish list
[[mawk_wish_list]]\\ mawk 1.3.4 from Thomas Dickey http://invisible-island.net/mawk/\\ his mawk is even . . . {{{ mawk.exe 1.3.4 %mawk% -v n=2e6 "BEGIN { while(n--) A[rand()]=rand(); for(i in A) j++; . . .
2K - last updated 2013-05-28 04:04 UTC by g0ph3r
MayorNumeroPreciso-español
La mayoría de las implementaciones usan números de coma flotante de alta precisión conocidos como "double" . . . número N deja de ser distinto de N+1: {{{ awk 'BEGIN{for (i = 0; i < 64; i++) printf "%s\t%19.0f\t%s\n", . . .
1K - last updated 2009-01-03 07:01 UTC by fcr
MostrarApostrofos-español
Esta pregunta es tan frecuente que merece su propia respuesta. Y aunque pareciera que esto es una limitación . . . uno puede correr los siguientes programas: {{{ BEGIN { print "dijo '¡Hola mundo!' y entonces devolvió . . . realizar algo similar en la consola: {{{ awk 'BEGIN{print "dijo '¡Hola mundo!' y entonces devolvió . . . hexa - parece funcionar al principio: {{{ awk 'BEGIN{print "dijo \x27¡Hola mundo!\x27 y entonces devolvió . . . de busybox y compare los resultados: {{{ awk 'BEGIN{print "\x27foo!\x27"}' }}} Notese que mientras . . .
4K - last updated 2009-01-15 20:03 UTC by fcr
numeric strings
Numeric strings obtained from the input source, will be treated as numeric values, when compared with . . . on which awk interpreter is being used: {{{ BEGIN { a=0 b=0 print "Test 1: 0 and 0" compare(a,b) . . .
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 . . . REs: {{{sh $ echo "foo" | /usr/xpg4/bin/awk 'BEGIN{re="o"} $0 ~ re {print}' foo $ echo "foo" | /usr/bin/awk . . . 'BEGIN{re="o"} $0 ~ re {print}' awk: syntax error near . . . explicit exit: {{{sh $ time /usr/xpg4/bin/awk 'BEGIN{print "begin"}' begin real 0m0.06s user 0m0.01s . . . sys 0m0.02s $ time /usr/bin/awk 'BEGIN{print "begin"}' begin ^?$ }}} ==== Can't delete . . .
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. {{{ . . .
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. {{{ . . .
1K - last updated 2008-11-24 08:07 UTC by pgas
PassingAnArray
* You can use split to create an array from a string: {{{ sh awk -v list='foo,bar,baz' ' BEGIN { n=split(list, . . .
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 . . . awk -v awkvar="$shellvariable" 'BEGIN{print awkvar}' }}} If you want to pass a pattern . . . the ENVIRON array: {{{ sh export FOO=bar awk 'BEGIN{print ENVIRON["FOO"]}' }}} If this is not enough . . .
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 . . . the file after running the awk program: {{{ awk 'BEGIN { printf("NEWVAR='%s'\n", somevalue) }' > . . . but this is also cumbersome: {{{ eval `awk 'BEGIN { print "NEWVAR=" somevalue }'` }}} Csh syntax . . .
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 . . . the file after running the awk program: {{{ awk 'BEGIN { printf("NEWVAR='%s'\n", somevalue) }' > . . . but this is also cumbersome: {{{ eval `awk 'BEGIN { print "NEWVAR=" somevalue }'` }}} Csh syntax . . .
1K - last updated 2008-11-24 08:05 UTC by pgas
precedence
The [[awk]] programming language uses rules of *precedence* to determine the order in which [[operator]]s . . . [[parentheses]] affects the value outside. {{{ BEGIN { # Changing the number variable in the middle . . .
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 . . . for (j = i * i; j < N; j += i) nums[j] = 1 } BEGIN { max = (ARGV[1] + 0); delete ARGV[1] alg = ARGV[2] . . .
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 . . . 0", one can run the following program: {{{ BEGIN { print "it said 'Hello, World!' and then returned . . . something similar on the command line: {{{ awk 'BEGIN{print "it said 'Hello, World!' and then returned . . . characters - seems to work at first: {{{ awk 'BEGIN{print "it said \x27Hello, World!\x27 and then . . . busybox awk and compare the results: {{{ awk 'BEGIN{print "\x27foo!\x27"}' }}} Note that [[mawk]] . . .
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。 . . . という文字列を表示して 0 を返すには、以下のようなプログラムで実行できます。 {{{ BEGIN { print "it said 'Hello, World!' and then returned . . . 0 } }}} しかしながら、同じことをコマンドラインで実行すると・・・ {{{ awk 'BEGIN{print "it said 'Hello, World!' and then returned . . . 進数のエスケープシーケンスですが、これは最初はうまく動作するように見えます。 {{{ awk 'BEGIN{print "it said \x27Hello, World!\x27 and then . . . の awk で以下の断片を実行して、結果を比較してみてください。 {{{ awk 'BEGIN{print "\x27foo!\x27"}' }}} mawk と buxybox の awk . . .
3K - last updated 2008-10-15 14:22 UTC by hi saito
PrintingNumbers
Use printf and a format string instead of print, some examples: {{{ awk BEGIN { printf "%f", 1000001.10 . . .
2K - last updated 2009-03-04 12:34 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| . . . the steps in C. It executes the one liner {{{awk BEGIN { print "hello, world" } }}} {{{ cc #include . . . = QSE_AWK_PARSESTD_CP; psin.u.cp = QSE_T("BEGIN { print \"hello, world\" }"); if (qse_awk_parsestd . . . script string MyAwk::SourceString in(QSE_T("BEGIN { print \"hello, world \" }")); if (awk.parse . . . == QSE_NULL) FAIL (awk); // execute the BEGIN, pattern-action, END blocks. MyAwk::Value r; . . .
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 . . . the field, including the now empty fields at the beginning and at the end, in the case of the above . . . then substr() to either trim it from the beginning or add that field and it's succeeding separator . . . } # remove fields 1 through start - 1 from the beginning for (i=1; i<start; i++) { if (match(str, . . . # the ending offset of the last field, from the beginning, is stored in "prev" prev = 0; # first, just . . .
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, . . . "/" as the only reasonable separator. {{{ awk BEGIN { RS = "/" cmd = "cd \""dir"\" && printf . . . This makes things a little simpler. {{{ awk BEGIN { RS = "\0\0" cmd = "cd \""dir"\" && . . .
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 . . . === Code {{{ awk #!/usr/bin/awk -f # by goedel BEGIN { include_path = "." iplen = split(include_path, . . .
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 . . . by the output from the function: {{{ awk BEGIN { # Creates a file foobar.txt # If the file already . . . will be appended to the end of the file: {{{ awk BEGIN { # Append a message to the end of the file foobar.txt . . .
2K - last updated 2011-06-25 05:12 UTC by pgas
regular expression operator
The [[awk]] programming language provides a set of *regular expression operators* that have special meanings . . . expression matches the left hand operand. {{{ BEGIN { text = "I like banana milkshake" if (text ~ . . . | *Purpose* | ^ | [[caret]] | Anchor matches the beginning of a string | $ | [[dollar]] | Anchor matches . . .
2K - last updated 2013-02-19 14:06 UTC by markhobley
repeat
A '''repeat loop''' is a [conditional loop] that repeatedly executes a block of instructions whilst the . . . cocomponent to produce a repeat loop: BEGIN { attempts = 1 do { print "Knock! Knock!" attempts . . .
1K - last updated 2011-08-14 16:00 UTC by markhobley
reverse
The [[awk]] extraction and reporting language does not provide a [[builtin]] function for reversing strings. . . . Call the reverse function to reverse our string BEGIN { print reverse("anut fo raj a rof tun A") } . . .
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, . . . done [tmp_key ] tmp_key = "" } } } # example BEGIN { a["b"] = 1 a[1] = "a" a[2] = "b" a[3] = "c" . . .
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 . . . like any other variable. This is often done in a begin block, before any input is read: {{{ BEGIN { . . . Following a blank line, the next record will not begin until a nonempty line follows. The following . . .
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 . . . length 0, conventionally it matches "before" the beginning of the string, "after" the end of the string, . . . expression, and as such it matches at the very beginning of the string. Since the regex engine does . . . have mattered, because at the same position (beginning of the string), four matches would be possible . . . then /b*/ just matches the empty string at the beginning, and there is no alternative between different . . .
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 . . . of the first one, with 7 quotes) awk 'BEGIN { q="'"'"'";print "Never say can"q"t."; exit . . . }' nawk -v q="'" 'BEGIN { print "Never say can"q"t."; exit }' awk 'BEGIN . . . print "Never say can"q"t."; exit }' awk 'BEGIN { q=sprintf("%c",39); print "Never say \"can"q"t.\""; . . . to know why you could not use this: {{{ awk 'BEGIN { q="\'"; print "Never say \"can"q"t.\""; exit . . .
2K - last updated 2008-11-19 07:41 UTC by pgas
ShellQuotingJapanese
シェルプログラミングの引用符、特に awk での引用符は初心者にとっては頭痛の種です。 Art Povelones は 1999 年 9 月 30 日にシェルでの引用符について長編のチュートリアルを投稿してくれました。これは非常に詳細過ぎるため . . . 7 つの引用符の使い方を用いたものがあります) (上記リンクの 7 つの各項目を参照) awk 'BEGIN { q="'"'"'";print "Never say can"q"t."; exit . . . }' nawk -v q="'" 'BEGIN { print "Never say can"q"t."; exit }' awk 'BEGIN . . . print "Never say can"q"t."; exit }' awk 'BEGIN { q=sprintf("%c",39); print "Never say \"can"q"t.\""; . . . }' }}} しかし、以下のものが使えないということを知っておくべきです。 {{{ awk 'BEGIN { q="\'"; print "Never say \"can"q"t.\""; exit . . .
2K - last updated 2008-11-22 11:16 UTC by 218.231.238.51.eo.eaccess.ne.jp
SimpleCalc
Simple 4 operations calculator ... {{{ awk # usage: print calc("5 * (1 + 2) * 5 + 7") # reads and update . . . postfixed) return eval(postfixed,len) } BEGIN { print calc("5.4 * (1 + -2) * 5 + 7") } }}} . . .
2K - last updated 2015-09-10 06:14 UTC by pgas
SpecialFile
You can use `-v rulesfile=filename' to process a file differently, like you would any other variable, . . . then use a `getline' loop (and `close') in your BEGIN statement. {{{ awk BEGIN \ { if (rulesfile=="") . . .
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, . . . then use a `getline' loop (and `close') in your BEGIN statement. {{{ awk BEGIN \ { if (rulesfile=="") . . .
1K - last updated 2008-11-24 08:09 UTC by pgas
statement
The [[awk]] extraction and reporting language is not [[imperative]]. However, [[action]]s within the . . . at the end of the line to be continued: {{{ BEGIN { # The backslash symbol can be used to spread . . .
2K - last updated 2011-05-21 16:43 UTC by markhobley
substr
=== Removing the first and last characters from a string === The following [[script]] demonstrates how . . . last [[character]]s from a [[string]]: {{{ awk BEGIN { mystring="knights" print substr(mystring,2) . . .
1K - last updated 2011-06-25 05:10 UTC by pgas
text.2.wiki.awk
#: C:\#\awk\lib\text.2.wiki.awk\\ . . . the clipboard\\ ## \\\\\ \\ BEGIN {\\ \\ . . .
11K - last updated 2012-09-24 14:55 UTC by g0ph3r
tracert.awk
{{{ awk #:: C:\_\_u\tracert.awk #: 2014-07-06 19:47:02 #:: rod.t_2014 #:: extract basename for tracert . . . functions: _dequote, _testf, _env, _dt ## _____ BEGIN { _nul = ""; _q = "|"; _sysmul = 1; _awkfile . . .
4K - last updated 2014-07-07 06:15 UTC by 212.205.56.222
Transpose
To transpose a N rows x M columns file into a M rows x N column file, one approach is to read the whole . . . fields; adapt to your real data): {{{ awk BEGIN{FS=","} {for(i=1;i<=NF;i++)a[NR,i]=$i} END{ . . .
1K - last updated 2011-03-20 06:53 UTC by ppp089210038204.dsl.hol.gr
truth
== Boolean Truth == A **boolean [[expression]]** has only two outcomes: **true** or **false**. In [[awk]], . . . "" and thus awk will not complain: {{{ sh $ awk 'BEGIN{if (true) {print "true"} else {print "false"}}' . . . empty string and evaluated as true: {{{ $ awk 'BEGIN{var = "0"; if (var) print "True!"}' # This gives . . . the quotes), it evaluates as false: $ awk 'BEGIN{var = 0; if (var) print "True!"}' # We get no . . . and netbsd awk version 20050424 {{{ sh nawk 'BEGIN{var="0"; foo=var+0;if (var){ print "true"}else{print . . .
3K - last updated 2013-02-20 17:34 UTC by markhobley
variable
A '''variable''' is a symbolic name associated with a [[value]]. A variable acts as a container and the . . . to a [[number]]. == Initialization within a begin block is possible == It is possible to initialize . . . variables in a BEGIN block to make them obvious and to make sure they . . . or [[underscore]] symbols, and may not begin with a [[digit]]. The awk interpreter is [[case . . . dog,Dog and DOG represent separate variables BEGIN { dog = "Benjamin" Dog = "Samba" DOG = "Bernie" . . .
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**. . . . # $1 matches, do something } }}} or {{{ awk BEGIN{var="abc(123)?r+"} $0 ~ var { # $0 matches, do . . .
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 . . . that declare and explain their arrays at the beginning. One must use comments for the purpose instead . . .
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 . . . contents of the book use `awk' (except at the beginning of sentences, as above). I will attempt to . . . do the same (except perhaps at the beginning of sentences, as above). Most implementations . . .
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 . . . contents of the book use `awk' (except at the beginning of sentences, as above). I will attempt to . . . do the same (except perhaps at the beginning of sentences, as above). Most implementations . . .
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 . . . Some awk implementations set the fields at the beginning of the block, and don't re-parse just because . . . set FS _before_ reading in a line. e.g., {{{ awk BEGIN { FS=":" } { print $1 } }}} e.g., {{{ awk -F: . . .
1K - last updated 2008-12-15 12:46 UTC by pgas
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