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Adler32Checksum
As documented in the [[http://en.wikipedia.org/wiki/Adler-32 | Adler-32 Wikipedia article]]. {{{ awk . . . a,b,len,i,j,MOD_ADLER,MAX_BLOCK) { if (!(sprintf("%c", int(rand()*256)) in ord)) for (i=0; i<256; . . . i++) ord[sprintf("%c",i)]=i # This table initialization should . . . 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 . . . specific file name) getline. e.g. if you want to print the first line of each of these files: {{{ sh . . . c d }}} you'd normally do: {{{ sh $ awk 'FNR==1{print}' file1 file2 a c }}} but if a "getline" snuck . . . of skipping the test for FNR==1 and so not printing the first line of the second file. {{{ sh . . . $ awk 'FNR==1{print}/b/{getline}' file1 file2 a }}} h) Using getline . . .
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 . . . | !/ | [[division]] | % | [[modulus]] {{{ awk print 6 + 3 # addition print 8 - 3 # subtraction print . . . 6 * 3 # multiplication print 10 / 4 # division print 10 % 4 # modulus }}} . . .
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 . . . awk #using a counter a[n++]="foo" a[n++]="bar" printf "the length of a is %d\n",n #remember that split . . . returns a value n=split("foo bar",a) printf "the length of a is %d\n",n # loop on the elements . . . always no need to know the length! for (i in a) print a[i] }}} Some awk implementations (gnu awk, true . . . you need to pass the length as an extra argument printf "In a function, the length of array is %d\n", . . .
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: . . . /EOF/{exit;}/#::/{next;}/----/{print;next;}{gsub(/\t/,(t)(t)t);gsub((FS)FS,t);print(($0)s);} . . .
5K - last updated 2014-08-04 03:23 UTC by y0tta
awk1page
an awk program is a series of //pattern { actions }// statements;\\ ie if the input line matchs pattern . . . then the actions are performed. {{{awk /abc/ { print } }}} would only print lines that contained the . . . line. Comments can follow the # symbol. {{{awk # print those lines where "awk" appears in the first . . . field. $1 ~ /awk/ { print $0; } }}} An omited pattern matchs every line . . . and an omitted action just prints the line.\\ The special pattern ''END'' is done . . .
2K - last updated 2012-03-18 22:22 UTC by g0pher
awk benchmarks
post awk benchmarks here:\\ see http://awk.freeshell.org/awk.exe for awks used here.\\ {{{awk C:\#> . . . -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))} . . . -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 Lucent Copyright notice
file FIXES from http://www.cs.princeton.edu/~bwk/btl.mirror/awk.zip ; version 20110810 {{{awk /***** . . . etc., 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) . . . }}} array SYMTAB holds info, eg: {{{awk BEGIN { _print_SYMTAB(); exit(0); } function _print_SYMTAB( . . . (varname != "SYMTAB") \ && (varname != "_print_SYMTAB")) \ printf(fmt, varname, SYMTAB[varname]) . . .
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] . . . DEBUG FUNCTIONS {{{ ----- function showop(op) { #print "op: " op >> "/dev/stderr" return } function . . . # PRIMITIVE OPERATOR FUNCTIONS {{{ ---- # -- printing commands function _dc_print(stk) { showop("print") . . . print stk[stk[SP]] } function _dc_prin(stk) { showop("prin") . . . printf stk[stk[SP]] } function _dc_xprint(stk, tos1, . . .
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 . . . |=print (and possibly others?) in for definition|yes?|yes|no|no|yes|no|unknown|yes|yes|yes| . . . FS to split characters|{{{echo abc|awk -F '' '{print NF}' # 3}}}| |=FS can match the empty string|{{{echo . . . aaba|awk -F 'b*' '{print NF}' # >2}}}| |=split() splits chars with . . . empty sep|{{{echo abc|awk '{print split($0,a,"")}' # >1; also try with //}}}| . . .
4K - last updated 2015-04-27 13:23 UTC by pgas
AwkGuide
** Work in Progress ** {{{ import from Mark Hobley's wiki }}} <toc> ---- == Overview * [[Overview]] . . . * [[pattern]]s * [[precedence]] * [[print]] * [[printf]] * [[putline]] * [[quotationmark]]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)} . . . file// \\prints lines from //file// containing //foo//\\ preceded . . .
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 . . . | 'prog'] [file ...] -version or --version; print version and exit; (was -V; prints: awk version . . . -d does debug dump examples: awk95 "BEGIN {print \"Hello, World!\"}" |- Hello, World! #: |- indicates . . . 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 . . .
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 . . . large use of these notions. Suppose one wants to print all the lines in a file that match some pattern . . . something like {{{ awk '{if ($0 ~ /pattern/) print $0}' }}} That works, but there are a number of . . . are very clear here: {{{ awk '$0 ~ /pattern/ {print $0}' }}} Our next step in the perfect awk-ification . . . is a match. Then we have: {{{ awk '/pattern/ {print $0}' }}} Now, let's turn our attention to the . . .
31K - last updated 2009-03-24 16:54 UTC by waldner
Backref2
The usual (and correct) answer for backreferences in awk (for example, the answer you can get on #awk . . . sed {{{ sed sed -n '/\(foo\)\(bar\).*\2\1/p' # prints lines with "foobar" and "barfoo" later in the . . . need: {{{ awk awk '{gsub(/^[a-z]*|[a-z]*$/,"");print}' # 1st example awk '{gsub(/^[^"]*"|"[^"]*$/,"");print}' . . .
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 . . . sed {{{ sed sed -n '/\(foo\)\(bar\).*\2\1/p' # prints lines with "foobar" and "barfoo" later in the . . . "c" $ echo 'a1-b2-c3-a5-s6-a7-f8-e9-a0' | gawk '{print gensub(/([ac])([0-9])/,"\\2+\\1","g",$0)}' 1+a-b2-3+c-5+a-s6-7+a-f8-e9-0+a . . . need: {{{ awk awk '{gsub(/^[a-z]*|[a-z]*$/,"");print}' # 1st example awk '{gsub(/^[^"]*"|"[^"]*$/,"");print}' . . .
3K - last updated 2010-12-30 06:53 UTC by ppp089210039107.dsl.hol.gr
BeforeAfterMatch
Problem: print the Nth record before or after a certain regular expression matches or, alternativley, . . . print every record except the Nth before or after a . . . regular expression matches. In the same way, print the N records before or after a certain match, . . . solutions for the "after match" part: i) Print the Nth record after some pattern: {{{ sh awk . . . 'c&&!--c;/pattern/{c=N}' file }}} ii) Print every record except the Nth record after some . . .
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** . . . commands: {{{ BEGIN { # This is a begin block print "The awk parser" # Print the title # Set the . . .
3K - last updated 2013-04-11 14:25 UTC by 92.40.253.171.threembb.co.uk
CAAN-or-caan
**caan: the comprehensive awk archive network**\\ -or-\\ . . . -v u=\136# -v v=\136-- $0~u{next}$0~v{print;next}/\173{{/,/\175}}/{print;next}{gsub((FS)FS,t);print(($0)s)} . . . \046 & \073 ; \136 ^ \173 { \175 } pclip prints the clipboard; clip copies to clipboard }}} . . .
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 . . . {{{ awk BEGIN { mystring = "I Like Apples" print (tolower(mystring)) print mystring } }}} == toupper . . . {{{ awk BEGIN { mystring = "I Like AppLes" print (toupper(mystring)) print mystring } }}} == These . . .
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 = "Benjamin" Dog = "Samba" DOG = "Bernie" printf "The three dogs are named %s, %s and %s.\n", . . .
1K - last updated 2011-06-25 05:14 UTC by pgas
Columnate
This script columnates the input file, so that columns line up like in the GNU column(1) command. Its . . . all the lines/records. At the END, the lines are printed in columnated format. If your terminal is not . . . split(line[nr], fields) for (f=1; f<nf; f++) printf "%-*s", max[f]+2, fields[f] print fields[f] . . .
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 . . . variable ARGC. {{{ awk #!/usr/bin/awk -f BEGIN { print "There are " ARGC "command line parameters" for(l=1; . . . l<ARGC; l++) { print "Argument " l " is " ARGV[l] } } }}} === The . . .
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 . . . a comment and is ignored by the awk interpreter print 'Hello!' # Comments after a hash sign are ignored . . .
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/ . . . answer]] ---- == How do I have dynamic-width printf strings, like C? <include "PrintfDynamicWidth"> . . . [[http://awk.freeshell.org/?action=edit;id=PrintfDynamicWidth| Edit this answer]] ---- == Why . . . Edit this answer]] ---- == Why does { FS=":"; print $1 } not split the first record? <include . . . Edit this answer]] ---- == Why does awk 'BEGIN { print 6 " " -22 }' lose the space? <include "ConcatenationPrecedence"> . . .
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/ . . . answer]] ---- == How do I have dynamic-width printf strings, like C? <include "PrintfDynamicWidthJapanese"> . . . [[http://awk.freeshell.org/?action=edit;id=PrintfDynamicWidthJapanese| Edit this answer]] . . .
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 . . . {{{ BEGIN { a="BALL" b="BELL" if (a == b) { print "The strings are equal" } if (a != b) { print . . . "The strings are not equal" } if (a > b) { print "The first string is lexically after than the . . . second" } if (a < b) { print "The first string is lexically before than the . . . second" } if (a >= b) { print "The first string is not lexically before than . . .
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 . . . action will be executed and the line will be printed. Note: For this example, join(1) is a working . . .
2K - last updated 2011-08-25 00:35 UTC by steve
concatenation
== The awk programming language does not have an explicit concatenation operator == The awk programming . . . the [[value]]s: {{{ awk BEGIN { name = "Bob" print "Hello " name } }}} === Numeric values will be . . . them: {{{ awk # This will output 234 BEGIN { print 2 3 4 } }}} === Precedence === Note that [[concatenation]] . . . # This will not produce a result of 358 BEGIN { print 2 3 4 + 1 2 3 # This actually produces 23523 . . .
1K - last updated 2011-06-25 05:13 UTC by pgas
ContextGrep
The following snippets print matching lines with surrounding context lines, like GNU grep's **grep -A . . . the time :) <toc> === Lines After === Printing the match followed by N lines is the easiest . . . to match), and **After** (the number of lines to print after each match). {{{ awk $0 ~ Pattern { # if . . . another block # and are outside a context block print "--" # ... print a divider afterlineno = NR + . . . -v N=3 '/Regex/{if (seen++ && NR>a+1)print "--"; a = NR+N} NR<=a' }}} === Lines Before . . .
3K - last updated 2011-07-01 08:32 UTC by pgas
continuation
Line continuation enables long lines of code to split across several lines for the purpose of making . . . used to spread a statement across several lines print \ "Hello World!" exit } }}} === Continuation . . . not split a regular expression # /foo\ # bar/ { print $1 } # Whitespace is the best place to split . . . a line /foobar / \ { print $1 } # Comments cannot be split with a backslash . . .
1K - last updated 2011-05-09 22:48 UTC by markhobley
control structure
'''Control structures''' are constructs used to control the logic of a program based on a given condition. . . . [[branch]]: {{{ awk if (guess == 6) { print "Wow! That was a lucky guess." # we are within . . . [[loop]]: {{{ awk for (l = 0; l <= 9; l++) { print l # This runs ten times } }}} . . .
1K - last updated 2011-06-25 05:08 UTC by pgas
ConvertHexToFloatingPoint
This code uses [[gawkism|gawk specific features]], such as the [[http://www.gnu.org/manual/gawk/html_node/Strtonum-Function.html][strtonum]] . . . if(sign) fval=fval*-1 return fval } BEGIN { } { print HexToFP($4, $3, $2, $1) # for use with test program . . . # print HexToFP($4, $3, $2, $1) " ?= " $5 } END { } }}} . . . { p=(char *)&f[j]; for(int i=0;i<4;i++) printf("%02x ",(*(p+i)&0xFF)); printf("%.3f\n",f[j]); . . . return fval } BEGIN { x = f_ieee754(0x41f24000) printf("x = %f\n",x) } you should get 30.28125 . . .
3K - last updated 2010-06-23 19:49 UTC by john b
DeleteTrailingNewlines
Simple oneliner that deletes the trailing newlines of a file: {{{ sh awk '!NF{b=b "\n";next} {printf . . . then skip the rest" * "If the line is not blank, print the accumulated newline, then the current line, . . . in b" The effect is that the newlines are only printed before non blank lines, the trailing newlines . . . are stored in b, but never printed. If you want to keep one trailing newline, . . . add one ;): {{{ sh awk '!NF{b=b "\n";next} {printf "%s%s",b,$0;b="\n"} END {print "\n"}' file }}} . . .
1K - last updated 2008-12-31 12:07 UTC by pgas
division
== Quotient Division == The [[slash]] symbol can be used as the division [[operator]] to produce the . . . results from a mathematical quotient: BEGIN { print int(22 / 6) } == Division by zero == Traditional . . . error in traditional awk implementations BEGIN { print 3 / 0 # inf } . . .
2K - last updated 2011-03-20 07:07 UTC by markhobley
dollarint
A [[dollar]] sign and followed by an [[integer]] are used to refer to [[field]]s within the current [[record]]: . . . {{{ awk { print $3 } # output field number three }}} Though you . . . are not limited to single digits: {{{ awk { print $123 } # output field number 123 }}} == Field . . . specify the field number: {{{ awk { myfield = 4 print $myfield # output field number 4 } }}} === Using . . . [[expression]] before the field number: {{{ awk print $(3 + 2) # output field number 5 # The parentheses . . .
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, . . . END{close(ARGV[1]) for(i=1;i<=NR;i++){ print line[i] > ARGV[1] } }' originalfile.txt }}} . . .
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]] . . . **END** label: {{{ END { # This is a begin block print "The end is here" # Print the closing message . . .
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. . . . ENVIRON["HOME"] might be "/home/chris". To print out all the names and values, use a simple loop: . . . {{{ awk for (i in ENVIRON) printf("ENVIRON['%s'] = '%s'\n", i, ENVIRON[i]) }}} . . . on Unix you can use a pipe from the `env' or `printenv' commands, but this is less pretty, and may . . . sub(/^[^=]*=/,"",varvalue) print "var [" varname "]='" varvalue "'" } }}} . . .
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. . . . ENVIRON["HOME"] might be "/home/chris". To print out all the names and values, use a simple loop: . . . {{{ awk for (i in ENVIRON) printf("ENVIRON['%s'] = '%s'\n", i, ENVIRON[i]) }}} . . . on Unix you can use a pipe from the `env' or `printenv' commands, but this is less pretty, and may . . . sub(/^[^=]*=/,"",varvalue) print "var [" varname "]='" varvalue "'" } }}} . . .
1K - last updated 2008-11-24 08:05 UTC by pgas
environment
The ENVIRON [[associative container]] contains the values of the current environment. This enables an . . . 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 . . . spaces) to awk, for instance: {{{ $1 ~ /bwk/ {print $5} }}} Note that there may not be any spaces . . . on comp.lang.awk): {{{ $ var="#" $ awk 'BEGIN{ print '"$var"' }' awk: cmd. line:1: BEGIN{ print # . . . in the awk program: {{{ $ var="#" $ awk 'BEGIN{ print "'"$var"'" }' # }}} However, there are cases . . . enough: {{{ $ var="hello world" $ awk 'BEGIN{ print "'"$var"'" }' awk: BEGIN{ print "hello awk: ^ . . .
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}' . . . awk にひとつの長い引数として送られます。 {{{ $1 ~ /bwk/ {print $5} }}} クォートされた部分の間のスペースはないかもしれないことに注意してください。一方、シングルクォートで括らない場合には、Unix . . . 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 awk: ^ . . .
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 . . . representation encoding. == Representation of nonprintable and control characters Escape sequences can . . . be used to represent [[nonprintable]] and [[control character]]s, such as [[tab]] . . . sequence in the middle of a [[literal string]]: print "first line \n second line" # The \n represents . . . to use a [[doublebackslash]] within the string: print "There is only one slash (\\) printed here."; . . .
3K - last updated 2008-12-30 13:07 UTC by Mark Hobley
exponent
==Warning! The use of [[gawkism]]s will prevent the script from running correctly on systems that use . . . producing a [[floating point]] value: {{{awk print (4 ** 3) # 64 (4 to the power of 3) }}} **Precedence** . . . than all other [[arithmetic]] operators: {{{awk print (2 * 4 ** 3) # 128 the exponent has a higher . . .
2K - last updated 2012-03-20 07:33 UTC by g0pher
field
In [[awk]] all [[input]] is separated into [[record]]s and each [[record]] is further divided into fields. . . . by using [[dollarint]] operator. {{{ awk { print $3 } # output field number three { print $12 . . .
1K - last updated 2011-06-25 05:31 UTC by pgas
field reference
== The field reference operator == The [[dollar]] symbol acts as a unary *field reference operator* and . . . number within the [[current record]]: {{{ { print $3 } # output field number three }}} === Field . . . numbers are not limited to single digits: {{{ { print $123 } # output field number 123 }}} ==== Using . . . to specify the field number: {{{ { myfield = 4 print $myfield # output field number 4 } }}} === Using . . . over the field reference operator: {{{ print $(3 + 2) # output field number 5 # The parentheses . . .
2K - last updated 2011-06-28 09:12 UTC by markhobley
FieldReference
$ is the "field reference" operator in AWK. It references the field in the current input record given . . . by the variable or constant. E.g. if you want to print the first field, the following are equivalent: . . . {{{ # print the first field using the '$' operator and a . . . constant. print $1; # same but with a variable instead of a constant . . . i = 1; print $i; }}} The power of awk is in learning to use . . .
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 . . . value in $3 of file.txt, print out the line from bit.txt where bit.txt:$1 == . . . close(BIT) while ((getline $0 < FILE) > 0) print (($3 in BL) ? BL[$3] : sprintf(ERRSTR, $3, BIT, . . . files: {{{ awk 'NR==FNR{BL[$1]=$0;next}$3 in BL{print BL[$3]}' bit.txt file.txt }}} For more information . . .
7K - last updated 2009-03-08 16:26 UTC by waldner
FileName
the file name is stored in the built-in variable FILENAME: {{{ awk '/^#include/ {print FILENAME,$2}' . . .
1K - last updated 2008-11-18 13:31 UTC by pgas
FileNameJapanese
the file name is stored in the built-in variable FILENAME: {{{ awk '/^#include/ {print FILENAME,$2}' . . .
1K - last updated 2008-11-24 08:08 UTC by pgas
FirstFile
you can tell if awk is parsing the first file given on the command line using FILENAME, thusly: {{{ awk . . . } rulesfile != FILENAME \ { if ($1 in replace) print replace[$1]; else print; } }}} Another way, using . . . { replace[$1] = $0; next } ($1 in replace) { print replace[$1]; next } { print } }}} . . .
1K - last updated 2008-11-18 13:34 UTC by pgas
FirstFileJapanese
you can tell if awk is parsing the first file given on the command line using FILENAME, thusly: {{{ awk . . . } rulesfile != FILENAME \ { if ($1 in replace) print replace[$1]; else print; } }}} Another way, using . . . { replace[$1] = $0; next } ($1 in replace) { print replace[$1]; next } { print } }}} . . .
1K - last updated 2008-11-24 08:09 UTC by pgas
FIXES
[[FIXES]] revised: . . . to the\\ printers in August, 1987."\\ (( . . . a filename (p 63).\\ added some missing ansi printf conversion letters: %i %X %E %G.\\ no . . . causes immediate advance to next input file.\\ printf("%c", 0) to include a null byte in output.\\ . . . that disables file output (print >, print >>),\\ process . . .
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 . . . line numbers to a file using [[awk]]: awk '{print FNR,$0 }' filename . . .
1K - last updated 2011-05-08 11:04 UTC by markhobley
FormatFileSizes
From time to time people ask how to sort the output of {{{du -h}}}. This is not particularly easy, since . . . for (i=3;i>=0;--i) { if ( size > 1024 ^i) {printf "%.2f%s\t%s\n",(size / 1024^i),u[i],name;next}}}' . . .
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]]) . . . <toc> ---- == How do I print a RangeOfFields, eg from field 2 to the end? . . . Edit this answer]] ---- == How do I print the LastField or the n'th field in a record? . . . Edit this answer]] ---- == I'm trying to print a number, why do I get 1e+06 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]] . . . awk 'BEGIN { FS = " " } { for (l=1;l<=NF;l++) print l ":" $l }' # This gives five fields, because . . . awk 'BEGIN { FS = "#" } { for (l=1;l<=NF;l++) print l ":" $l }' }}} == Matching a single space delimiter . . . 'BEGIN { FS = "[ ]" } { for (l=1;l<=NF;l++) print l ":" $l }' }}} == Leading and trailing whitespace . . . Custard Bananas '| awk 'BEGIN { FS = " " } { print $2 }' # This gives Custard echo ' Rhubarb 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. . . . # prepend/append other text # rep[i] = sprintf("%05d", mtch[i]*4) # arithmetic (like perl) . . . text newstring=BuildNew(n,$0,mtch,start,rep) print newstring } }}} Now that a generic framework . . .
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 . . . socket = "/inet/tcp/0/" host "/80" printf "GET / HTTP/1.1\r\nHost: %s\n\n", host |& . . . socket for (header in headers) { printf "%s\r\n", headers[header] |& socket } printf . . . = getcoord(coords[3]) lon = getcoord(coords[4]) printf "http://maps.google.com/maps?q=%s,%s\n", lat, . . .
1K - last updated 2011-11-14 16:35 UTC by pgas
hash
== Prefixing comments == The hash symbol can be used as a prefix for inserting comments within an [[awk]] . . . a comment and is ignored by the awk interpreter print 'Hello!' # Comments after a hash sign are ignored . . .
1K - last updated 2010-11-08 22:37 UTC by markhobley
Hello World in awk
This example program outputs the words "hello world" to the terminal: {{{ awk # Hello World BEGIN { print . . . a comment and is ignored by the awk interpreter print 'Hello' # Comments after a hash sign are ignored . . . of code that the [[function]] contains. === The print statement The first [[statement]] within the . . . [[main]] function calls the [[print]] statement with a [[string]] of [[character]]s, . . .
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]]** . . . awk * [[Columnate]] a file * [[ContextGrep]] -- print context lines around a match * [[Shellquote]] . . . / mib's FileAndBitJoinClone, which was used to print out the lines from an input file called bit.txt . . .
5K - last updated 2023-06-26 04:15 UTC by HappMacDonald
if
The if [[condition]]al construct allows a [[statement]] or [[block]] of code to be [[condition]]ally . . . STATEMENT == For example: {{{ if (guess == 6) print "Wow! That was a lucky guess." }}} == There are . . . squiggly [[brace]]s: {{{ if (guess == 6) { print "Wow! That was a lucky guess." # Multiple statements . . . second block is executed: {{{ if ($guess == 6) print 'Wow! That was a lucky guess!' else print 'Sorry! . . .
2K - last updated 2011-09-11 21:43 UTC by 92.40.253.171.threembb.co.uk
include
The [[awk]] extraction and reporting language does not support the use of include files. However, it . . . { sayhello() } # two.awk function sayhello() { print "Hello world" } }}} === _Function names must . . .
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 . . . then a value of [[zero]] is returned: BEGIN { print index("Staffordshire","ford") # 5 } === Case . . .
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]]**. . . . / mib's FileAndBitJoinClone, which was used to print out the lines from an input file called bit.txt . . .
7K - last updated 2009-02-12 23:31 UTC by fcr
Invoking an awk program
=== Throwaway one-liners It is often useful to type a simple program at the command line for use within . . . of the [[awk]] command: {{{ sh awk 'BEGIN {print "Hello World!"}' }}} === Running an awk script . . . as follows: {{{ sh #!/usr/bin/awk -f BEGIN { print "Hello World!" } }}} === Using awk as a filter . . .
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 . . . an [iterator] value. The [block] containing the [print] statement in the following example runs for . . . [loop]: BEGIN { for (l= 0; l <= 9; l++) { print l } } === _Elements of a for loop_ The [parentheses] . . . of l reaches 10: for (l= 0; l <= 9; l++) { print l } ==== _Continuation statement_ The continuation . . .
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. . . . {{{ sh awk 'BEGIN{for (i = 0; i < 64; i++) printf "%s\t%19.0f\t%s\n", i, 2^i, (((2^i+1) == (2^i))? . . . "in" : "") "accurate"}' }}} This will print out a list of numbers. The largest reliable value . . .
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 . . . take the time to read this whole faq {{{ awk print $1 # prints the first field print $(10-9) # again . . . the first field i=1;print $i # yes it prints the first field print $NF . . . # prints the last field print $(NF-1) # prints the field . . .
2K - last updated 2009-02-05 22:43 UTC by firebush.stsci.edu
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 . . . memoization new = levdist(words[i], words[j]) print words[i], words[j], new if (new > max) { max . . . = (words[i] " - " words[j] ": " new) } } } print bestpair } }}} ==== Unit tests {{{ awk #!/usr/bin/awk . . . levdist(str1, str2) if (testval == correctval) { printf "%s:\tCorrect distance between '%s' and '%s'\n", . . . testval, str1, str2 return 1 } else { print "MISMATCH on words '%s' and '%s' (wanted %s, . . .
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 . . . 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 . . . single rule to span multiple lines /foobar/ \ { print $1 } }}} Note that line continuation characters . . .
1K - last updated 2011-05-17 23:24 UTC by markhobley
literal characters
== Special characters cannot be directly included in a literal string == Special characters, such as . . . is used to represent a newline character: {{{ print "first line\nsecond line" # The \n represents . . . an embedded newline character and should print as follows: {{{ first line second line }}} . . .
2K - last updated 2010-11-28 19:14 UTC by markhobley
logical operator
In [[awk]], *logical operators* are used to perform [[boolean]] operations, and a return a value of [true] . . . expressions, a non null string is true: {{{ awk print (0 && 0) # 0 (false) print (0 && . . . 7) # 0 (false) print (7 && 0) # 0 (false) print (7 && . . . 2) # 1 (true) print (2 && 7) # 1 (true) print ("" && . . . "") # 0 (null strings are treated as false) print ("apples" && "pears") # 1 (true) print . . .
3K - last updated 2009-01-02 11:13 UTC by pgas
LoopOnFields
Fields are numbered from 1 to NF, so you can easily use a for loop, and the derefence operator, for instance . . . to print each field matching foo: {{{ awk for (i=1;i<=NF;i++) . . . { if ($i ~ /foo/) { print $i } } }}} . . .
1K - last updated 2009-03-17 21:09 UTC by waldner
LshalOutputParser
=== Problem Specification 10:50 <Thanatermesis> i want to obtain the model of the disk, for example, . . . = 1 inBlock = 0 FS = " = " } function die(msg) { printf "ERROR on line %d of input: %s\n", NR, msg >> . . . info } else { type = "udi" val = trim($2) } #printf "!%s! ---- !%s! ---- !%s!\n", key, val, type . . . \ length(PROPERTIES["storage.model"]) > 2) { printf "device:\t%s\nmodel:\t%s\n", PROPERTIES["block.storage_device"], . . .
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 . . . {{{ BEGIN { # This is our main startup procedure print "Hello World!" } }}} . . .
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 . . . { while(n--) A[rand()]=rand(); for(i in A) j++; print j;}" took 9.2 seconds whereas gawk.exe 4.0.1 . . .
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" . . . N+1: {{{ awk 'BEGIN{for (i = 0; i < 64; i++) printf "%s\t%19.0f\t%s\n", i, 2^i, (((2^i+1) == (2^i))? . . .
1K - last updated 2009-01-03 07:01 UTC by fcr
modulus
The [[dyadic]] modulus [[operator]], represented by a [[percent]] sign is used to return the remainder . . . in division [[arithmetic]]: print 15 % 4 # 3 (the remainder of 15 divided by 4) . . . 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
MostrarApostrofos-español
Esta pregunta es tan frecuente que merece su propia respuesta. Y aunque pareciera que esto es una limitación . . . la secuencia de escape en base ocho ('\047') o printf ('print "%c", 39'). No use las secuencias de . . . correr los siguientes programas: {{{ BEGIN { print "dijo '¡Hola mundo!' y entonces devolvió 0" exit . . . algo similar en la consola: {{{ awk 'BEGIN{print "dijo '¡Hola mundo!' y entonces devolvió 0";exit . . . - parece funcionar al principio: {{{ awk 'BEGIN{print "dijo \x27¡Hola mundo!\x27 y entonces devolvió . . .
4K - last updated 2009-01-15 20:03 UTC by fcr
Newline
"print" prints a newline by default. If you don't want a newline, you can use printf instead it is straightforward, . . . string and avoid putting data in it. {{{ awk printf "%s",$0 #prints the record without adding a . . . you can do something like: {{{ sh awk '{printf "%s%s",separator,$0;separator="|"}END{printf . . . "\n"}' }}} "print" does print a newline by default, but that's . . . not the whole truth, in fact print adds the character in ORS, so you can also change . . .
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]]. . . . last [[field]] from each [[record]]: {{{ awk '{ print $1,$NF }' filename }}} . . .
1K - last updated 2011-05-28 15:14 UTC by markhobley
numeric strings
Numeric strings obtained from the input source, will be treated as numeric values, when compared with . . . interpreter is being used: {{{ BEGIN { a=0 b=0 print "Test 1: 0 and 0" compare(a,b) a="0" b=0 print . . . "Test 2: '0' and 0" compare(a,b) a="0.0" b=0 print "Test 3: '0.0' and 0" compare(a,b) a="0.0" b="0" . . . print "Test 4: '0.0' and '0'" compare(a,b) a="00" b="0" . . . print "Test 5: '00' and '0'" compare(a,b) a="00" b=0 . . .
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 . . . {{{sh $ echo "foo" | /usr/xpg4/bin/awk '1{print}' foo $ echo "foo" | /usr/bin/awk '1==1{print}' . . . foo $ echo "foo" | /usr/bin/awk '1{print}' awk: syntax error near line 1 awk: bailing . . . near line 1 $ echo "foo" | /usr/bin/awk '1==1{print}' foo $ echo "foo" | /usr/xpg4/bin/awk '!x{print}' . . . foo $ echo "foo" | /usr/bin/awk '!x{print}' awk: syntax error near line 1 awk: bailing . . .
5K - last updated 2012-01-24 08:29 UTC by pgas
OpeningFiles
You can open files dynamically using `getline', `close', and `print EXPR > FILENAME', like: {{{ awk . . . while ( (getline aline < infilename) >0 ) print(aline aline) > outfilename; close(infilename); . . .
1K - last updated 2008-11-18 13:33 UTC by pgas
OpeningFilesJapanese
You can open files dynamically using `getline', `close', and `print EXPR > FILENAME', like: {{{ awk . . . while ( (getline aline < infilename) >0 ) print(aline aline) > outfilename; close(infilename); . . .
1K - last updated 2008-11-24 08:09 UTC by pgas
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="$shellvariable" 'BEGIN{print awkvar}' }}} If you want to pass a pattern as . . . /. {{{ sh #version using a constant awk '/foo\./{print}' #version with a variable pattern='foo\\.' awk . . . -v pattern="$pattern" '$0 ~ pattern{print}' }}} If your variable is an environment variable . . . ENVIRON array: {{{ sh export FOO=bar awk 'BEGIN{print ENVIRON["FOO"]}' }}} If this is not enough have . . .
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 . . . after running the awk program: {{{ awk 'BEGIN { printf("NEWVAR='%s'\n", somevalue) }' > /tmp/awk.$$ . . . this is also cumbersome: {{{ eval `awk 'BEGIN { print "NEWVAR=" somevalue }'` }}} Csh syntax and more . . .
1K - last updated 2008-11-19 07:45 UTC by pgas
PassingVariablesToTheParentProcessJapanese
How can I put values into the environment of the program that called my awk program? Short answer, you . . . after running the awk program: {{{ awk 'BEGIN { printf("NEWVAR='%s'\n", somevalue) }' > /tmp/awk.$$ . . . this is also cumbersome: {{{ eval `awk 'BEGIN { print "NEWVAR=" somevalue }'` }}} Csh syntax and more . . .
1K - last updated 2008-11-24 08:05 UTC by pgas
pattern
In [[awk]], patterns are used to select lines of input for processing. The pattern within each [[rule]] . . . In the following example, the [[action]] (to print the line) will occur for each line that match . . . the [[regular expression]] foobar. {{{ /foobar/ {print $0} }}} === Start and End Patterns === It is . . . within the pattern evaluates to [[true]]: {{{ 0 {print "Hello"} # This will not cause output, because . . . a value of zero is considered to be false 1 {print "Goodbye"} # This will cause output, because . . .
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 . . . than [[addition]], so it is performed first. {{{ print 3 + 4 * 5 # This produces 23 because multiplication . . . so their contents are evaluated first: {{{ print (3 + 4) * 5 # The parentheses cause the addition . . . occurs before the [[addition]]: {{{ print 3 * (4 + 2 * 3) # Within the parentheses 2 * . . . the [[expression]] before the [[addition]]: {{{ print 5 - 2 + 1 }}} == _Side Effects_ An expression . . .
7K - last updated 2013-04-11 06:58 UTC by markhobley
PreguntasFrecuentes
<toc> ---- == ¿Cómo muestro un rango de campos? Desde [[RangoDeCampos-español]], [[http://awk.freeshell.org/es?action=edit;id=RangoDeCampos-espa%C3%B1ol| . . . ---- == ¿Cómo usar printf? Desde [[printf-español]], [[http://awk.freeshell.org/es?action=edit;id=printf-espa%C3%B1ol|editar]]: . . . <include "printf-español"> ---- == ¿Cómo encontrar el mayor . . . ---- == ¿Por qué «print $variable» no muestra nada? ¿por qué «print "hola . . .
2K - last updated 2009-01-03 03:01 UTC by fcr
PrimeNumberSieve
This is the standard sieve of Eratosthenes implemented in portable awk. The running time of the bare . . . primes) } #for (i = 0; i in primes; i++) printf "%2s: %3d\n", i, primes[i] } }}} === Methodology . . .
4K - last updated 2008-06-19 05:56 UTC by gnomon
print
== Usage == === print [ LIST ] === The [[variadic]] **print** function is used to produce simple standardized . . . in the [[argument]] list. == Examples == print "Hello" == Default value == If the print function . . . record: {{{ # These two commands are equivalent print $0 print }}} == Default action == Note that the . . . default [[action]] within a [[rule]] is to print all [[line]]s that match the [[pattern]]. This . . . means that an [[action]] to just print a matching line can be omitted altogether. . . .
1K - last updated 2011-05-11 15:10 UTC by markhobley
PrintASingleQuote
This question gets asked often enough that it deserves its own answer. This common question doesn't actually . . . Story Use octal [[escape sequence]]s ('\047') or printf ('printf "%c", 39'). Do not use hex escape sequences . . . === The Rambling Tale In order to print out the string "it said 'Hello, World!' and then . . . one can run the following program: {{{ BEGIN { print "it said 'Hello, World!' and then returned 0" . . . similar on the command line: {{{ awk 'BEGIN{print "it said 'Hello, World!' and then returned 0";exit . . .
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。 . . . === 小話 8 進数のエスケープシーケンス ('\047') または printf ('printf "%c", 39') を用いてください。 16 進数のエスケープシーケンス . . . 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 0";exit . . . {{{ awk 'BEGIN{print "it said \x27Hello, World!\x27 and then returned . . .
3K - last updated 2008-10-15 14:22 UTC by hi saito
printf-español
Muestra todas las palabras en cada línea: {{{ awk '{for(i=1;i<=NF;++i) printf "%s ", $i;print ""}' . . . en cada línea: {{{ awk '{for(i=2;i<=NF;++i) printf "%s ", $i;print ""}' nombredearchivo }}} Muestra . . . start=3 -v end=5 '{ for(i=start;i<=end;i++) printf "%s ", $i;print "" }' nombredearchivo }}} Muestra . . . en cada línea: {{{ awk '{ i=0; while(++i<8) printf("%s ", $i); print $i }' nombredearchivo }}} . . . los saltos de línea en un archivo: {{{ awk '{ printf "%s ", $O }' nombredearchivo }}} Muestra todo . . .
1K - last updated 2009-01-03 02:53 UTC by fcr
printf
== Usage == === printf [ FORMAT, LIST ] === The **printf** [[variadic]] function provides generic [[string . . . [[standard output]] in a similar manner to the printf function used in the C programming language. . . . The printf function uses the same string formatting functions . . . as [[sprintf]], but printf does not automatically append . . . or [[newline]] character to its output. The printf function provides support for the complete set . . .
2K - last updated 2011-06-09 20:34 UTC by markhobley
PrintfDynamicWidth
With modern awks, you can just do it like you would in C (though the justification is less clear; C doesn't . . . maxlen=length(arr[i]) for (i in arr) printf("%-*s %s\n",maxlen,arr[i],i) }}} With old awks, . . . (maxlen<length(arr[i])) maxlen=length(arr[i]) printfstring="%-" maxlen "s %s\n"; for (i in arr) printf(printfstring,arr[i],i) . . .
1K - last updated 2008-11-24 08:26 UTC by pgas
PrintfDynamicWidthJapanese
With modern awks, you can just do it like you would in C (though the justification is less clear; C doesn't . . . maxlen=length(arr[i]) for (i in arr) printf("%-*s %s\n",maxlen,arr[i],i) }}} With old awks, . . . (maxlen<length(arr[i])) maxlen=length(arr[i]) printfstring="%-" maxlen "s %s\n"; for (i in arr) printf(printfstring,arr[i],i) . . .
1K - last updated 2008-11-24 08:36 UTC by pgas
PrintingNumbers
Use printf and a format string instead of print, some examples: {{{ awk BEGIN { printf "%f", 1000001.10 . . . #prints 1000001.100000 printf "%.3f", 1000001.10 #prints . . . 1000001.100 printf "%ld",1000001000000001} #prints 1000001000000001 . . . } }}} For more information about printf see [[http://www.gnu.org/software/gawk/manual/html_node/Printf.html#Printf|the . . . in the first place? awk does something like printf using the format string in the variable OFMT, . . .
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 . . . one (like tr -s '\n'), assumes a bourne shell printf "%s\n" foo '' '' bar | awk $$${$+ RS=} #another . . .
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| . . . in C. It executes the one liner {{{awk BEGIN { print "hello, world" } }}} {{{ cc #include <qse/awk/std.h> . . . #define FAIL(msg) do { qse_printf(QSE_T("ERR: %s\n"),msg); goto oops; } while(0) . . . QSE_AWK_PARSESTD_CP; psin.u.cp = QSE_T("BEGIN { print \"hello, world\" }"); if (qse_awk_parsestd (awk, . . . string MyAwk::SourceString in(QSE_T("BEGIN { print \"hello, world \" }")); if (awk.parse (in, MyAwk::Source::NONE) . . .
4K - last updated 2011-10-27 06:25 UTC by pgas
RangeOfFields
Printing a range of fields - all fields but the first, for examples, or fields 3 through 8 - is a surprisingly . . . = $2 = ""; for (i = 9; i <= NF; i++) $i = ""; print} }}}). This will however cause awk to recompute . . . ... NF=8-3+1 # only keep the first six fields print }}} ==== Drawbacks of using a loop In some cases, . . . everything before a certain field and then print out the rest of the line. The typical tactic . . . {{{ bash awk '{sep="";for (i=2;i<=NF;i++) {printf "%s%s",sep, $i;sep=" "}; printf "\n"}' file . . .
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, . . . BEGIN { RS = "/" cmd = "cd \""dir"\" && printf '%s/' *" while (cmd | getline > 0) if ($0) . . . files[n++] = $0 close(cmd) for (f in files) printf("/%s/\n", files[f]) } }}} Assuming that dir . . . { RS = "\0\0" cmd = "cd \""dir"\" && printf '%s\\0' *" cmd | getline close(cmd) patsplit($0, . . . files, "[^\0]+") for (f in files) printf("/%s/\n", files[f]) } }}} Here we can read in . . .
2K - last updated 2013-10-03 22:35 UTC by emg
ReadMultipleFiles
awk automatically reads multiple files (under Unix at least) -- use something like: {{{ awk '/^#include/ . . . {print $2}' *.c *.h }}} . . .
1K - last updated 2008-11-18 13:30 UTC by pgas
ReadMultipleFilesJapanese
awk automatically reads multiple files (under Unix at least) -- use something like: {{{ awk '/^#include/ . . . {print $2}' *.c *.h }}} . . .
1K - last updated 2008-11-24 08:08 UTC by pgas
Recursively Include C headers
=== Problem Specification i want to generate one big .hpp file out of multiple .hpp files and want to . . . = "." iplen = split(include_path, ip, /:/) } { print_line($0) } function print_file(file, line) { . . . while (getline line < file > 0) print_line(line) close(file) } function print_line(line, . . . in list_of_paths)) { list_of_paths[file] = 1 print_file(file) } } else print line } function complete_path(file, . . . if (p !~ /\/$/) p = p "/" p = p file if (system(sprintf("/usr/bin/test -f \"%s\"", p)) == 0) return . . .
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 . . . already exists, its contents will be overwritten print "Hello" > foobar.txt } }}} A doublebeak symbol . . . a message to the end of the file foobar.txt print "Hello" >> foobar.txt } }}} == Redirection . . . redirection to an external cat command: {{{ awk print "TST60000 An error has occured!" | "cat 1>&2" . . . redirection can be made to this device: {{{ awk print "TST60000 An error has occured!" > /dev/stderr . . .
2K - last updated 2011-06-25 05:12 UTC by pgas
ReferenciarCampos-español
En AWK, $ es el operador para "referenciar campos". Justamente referencia el campo del registro de entrada . . . campo usando el operador '$' y una constante. print $1; # o con una expresión equivalente: print . . . una variable en lugar de una constante: i = 1; print $i; }}} El poder de awk se encuentra en aprender . . . {{{ # muestra el valor de i y el campo i-ésimo. print i, $i; # muestra el campo i-ésimo, pero sólo . . . si es distinto del string vacío: if ($i != "") print $i; }}} . . .
1K - last updated 2009-01-03 03:06 UTC by fcr
regular expression operator
The [[awk]] programming language provides a set of *regular expression operators* that have special meanings . . . "I like banana milkshake" if (text ~ /banana/) { print "Match found" } } }}} Negation can be achieved . . . not operator: {{{ if (text !~ /strawberry/) { print "Match not found" } }}} == _A binding operator . . . expression is used as a pattern /rhubarb/ {print $0} }}} === _Substitution cannot be performed . . . milkshake" if (text ~ s/banana/chocolate/) { print "Substitution made" print text } }}} == _Basic . . .
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 . . . produce a repeat loop: BEGIN { attempts = 1 do { print "Knock! Knock!" attempts = attempts + 1 } while( . . .
1K - last updated 2011-08-14 16:00 UTC by markhobley
RepeatAString
Sometimes it is useful to have something like Perl's 'x' operator, which repeats a string N times. This . . . linear, very compacted, ones based on using {{{printf()}}} and {{{gsub()}}}), but tests showed them . . .
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. . . . 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, . . . 1 a[1] = "a" a[2] = "b" a[3] = "c" for (k in a) printf("a[%s] = %s\n", k, a[k]) reverse_mapping(a) . . . printf("\n") for (k in a) printf("a[%s] = %s\n", k, . . . a[k]) } }}} The example shown prints: {{{ a[b] = 1 a[1] = a a[2] = b a[3] = c a[a] . . .
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 . . . to an empty string: {{{ #!/bin/sh awk -v'' '{ print $1,$3 }' /home/accounts/transdata.fil }}} Remember . . .
3K - last updated 2013-02-19 23:11 UTC by markhobley
SandBox2
escaping {{{ \\ }}} a \ \ -- {{{ ** }}} **{{{ ** }}}** //**{{{ ** }}}**// \\ line break using\\\\ two . . . awk]]\\ prints as [ awk] instead of [opengroup.org awk]\\ [[http://pubs.opengroup.org/onlinepubs/9699919799/utilities/awk.html . . . awk]]\\ puting a leading space; makes it print as expected. A bug or a feature ??\\ Never mind; . . .
2K - last updated 2012-09-16 08:46 UTC by g0ph3r
SedFAQ
<toc> ---- == I have a line like "abdcgfjeuPATTERNfjfhghj", I want to get the PATTERN part, why . . . within the line, PATTERN with itself. Then, sed prints what's in the pattern space, which is still . . . of PATTERN will be left unchanged and printed, which is probably not what you want. Alternatively, . . . -n is used, and interesting bits are explicitly printed after the replacement (adding some /p switches . . . at a time from lines that have matches, and print it. Then, record in the hold space that we have . . .
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** . . . { gsub(/'/, "'\\''", str) return sprintf("'%s'", str) } }}} . . .
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 . . . {{{ cat <<'@@' > /tmp/never$$.awk { print "Never say can't." } @@ awk -f /tmp/never$$.awk; . . . first one, with 7 quotes) awk 'BEGIN { q="'"'"'";print "Never say can"q"t."; exit }' nawk -v q="'" 'BEGIN . . . { print "Never say can"q"t."; exit }' awk 'BEGIN { q=sprintf("%c",39); . . . print "Never say can"q"t."; exit }' awk 'BEGIN { q=sprintf("%c",39); . . .
2K - last updated 2008-11-19 07:41 UTC by pgas
ShellQuotingJapanese
シェルプログラミングの引用符、特に awk での引用符は初心者にとっては頭痛の種です。 Art Povelones は 1999 年 9 月 30 日にシェルでの引用符について長編のチュートリアルを投稿してくれました。これは非常に詳細過ぎるため . . . {{{ cat <<'@@' > /tmp/never$$.awk { print "Never say can't." } @@ awk -f /tmp/never$$.awk; . . . (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 { q=sprintf("%c",39); . . . print "Never say can"q"t."; exit }' awk 'BEGIN { q=sprintf("%c",39); . . .
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 . . . = stack[head] head -= 1 } if (head == 0) { print "Syntax Error" return 0 } else { head -= 1 } . . . 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
slash
== Division Operator == The slash symbol is used as the division operator to produce the [[result]]s . . . regular expression used as a pattern /foobar/ { print $0 } }}} . . .
1K - last updated 2011-05-11 15:00 UTC by markhobley
SpecialFile
You can use `-v rulesfile=filename' to process a file differently, like you would any other variable, . . . {{{ awk BEGIN \ { if (rulesfile=="") { print "must use -v rulesfile=filename"; exit(1); } . . . close(rulesfile); } { if ($1 in replace) print replace[$1]; else print; } }}} . . .
1K - last updated 2008-11-18 13:37 UTC by pgas
SpecialFileJapanese
You can use `-v rulesfile=filename' to process a file differently, like you would any other variable, . . . {{{ awk BEGIN \ { if (rulesfile=="") { print "must use -v rulesfile=filename"; exit(1); } . . . close(rulesfile); } { if ($1 in replace) print replace[$1]; else print; } }}} . . .
1K - last updated 2008-11-24 08:09 UTC by pgas
SplitIntoChars
In portable POSIX awk, the only way to do this is to use substr to pull out each character, one by one. . . . anarray, "\001") for (i=1;i<=n;i++) print "character " i "is '" anarray[i] "'"; }}} . . .
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. . . . anarray, "\001") for (i=1;i<=n;i++) print "character " i "is '" anarray[i] "'"; }}} . . .
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 . . . used to spread a statement across several lines print \ "Hello World!" exit } }}} == Continuation characters . . . using a continuation character /foo\ bar/ { print $1 } }}} . . .
2K - last updated 2011-05-21 16:43 UTC by markhobley
string manipulation function
The [[awk]] programming language provides a set of [[builtin]] functions for performing various string . . . * [[length]] * [[match]] * [[split]] * [[sprintf]] * [[sub]] * [[substr]] * [[case conversion|tolower]] . . .
1K - last updated 2011-06-07 00:35 UTC by markhobley
StyleSheet
body { background-color:#FFF; color:#000; margin:1em 2em; } textarea { width:100%; } a:link { color:#00F; . . . } div.near p { margin-top:0; } @media print { body { font:12pt sans-serif; } a, a:link, a:visited . . . { background-color:#faf; } @media print { div.month { display: none; } div.year div.month . . . dd { margin-left:15ex; } /* page trail */ @media print { span.trail { display: none; }} /* portrait . . . padding-right:5%; font-size:smaller; } @media print { div.refer { display:none; }} /* usemod, tables, . . .
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 . . . a [[string]]: {{{ awk BEGIN { mystring="knights" print substr(mystring,2) # remove the first letter . . . print substr(mystring,1,length(mystring)-1) # remove . . . the last character print substr(mystring,2,length(mystring)-2) # remove . . .
1K - last updated 2011-06-25 05:10 UTC by pgas
text.2.wiki.awk
#: C:\#\awk\lib\text.2.wiki.awk\\ . . . Prints results to stdout and copies to the clipboard.\\ . . . if(_debug) for(i in B) { print(_qt_(++j, "B[]", i, B[i])); fflush(); . . . if(_debug) for(i in A) { print(_qt_(++k, "A[]", i, A[i])); fflush(); . . . if(_debug) { print(_qt_("_in_escape:", _in_escape, t, "end")); . . .
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 . . . to (nojoy inside [[ ]]) #: Prints results to stdout and copies to the clipboard. . . . use "\\&" t = t ? (t "\n" s) : s; } END { print(t); print(t) | "%u%gclip.exe"; } ## _____ #: . . . show|hide|min|max exefile opts #: shexec open|print filename #: \a \007 sp\040 !\041 "\042 #\043 . . .
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 . . . - pclip prints clipboard #:: usage: pclip | awk64 -f C:\_\_u\tracert.awk . . . = _dtcmd "%M:%S.00'"; } if(cmd) _cmd = cmd; print("\n\t" _dt() "\t" _awk, "-f " _awkfile, \ "\n\t_cmd . . . if(_test) _testf(); } 1 { if(NR == 1) print(" $0 =", (_q)($0)_q); else print("\n $0 =", (_q)($0)_q); . . . s = $0 = _dequote($0); print(" s =", (_q)($0)_q); match(s, /([a-z0-9-]+[.])+[a-z0-9-]+/); . . .
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 . . . in memory as a bidimensional array, and finally print it transposing rows and columns (the example . . . line=line sep a[j,i] sep=FS } print line line=sep="" } } }}} NR is our N, and NF . . . and after N values are concatenated, the line is printed and set back to empty, ready for building the . . .
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]], . . . not complain: {{{ sh $ awk 'BEGIN{if (true) {print "true"} else {print "false"}}' false }}} | **Value** . . . to false: {{{ sh echo 00 | awk'{if ($1) {print "true"}else{print "false"}}' false # $1 is the . . . as true: {{{ $ awk 'BEGIN{var = "0"; if (var) print "True!"}' # This gives the same result with var . . . as false: $ awk 'BEGIN{var = 0; if (var) print "True!"}' # We get no output because evaluation . . .
3K - last updated 2013-02-20 17:34 UTC by markhobley
variable-español
AWK no es el shell, y tampoco es Perl. Antes que nada, las variables en AWK se referencian utilizando . . . «nombre» (al igual que en C) {{{ awk '{var="foo";print var}' }}} AWK es como C (no el shell), no expande . . . la concatenación de un string y una variable print "hola " nombre; # concatena, asigna a «newstr» . . . y lo muestra newstr = "hola " nombre; print newstr; # print también reconoce la «,» como . . . lo siguiente es equivalente al # ejemplo previo: print "hola", nombre; }}} . . .
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 . . . { dog = "Benjamin" Dog = "Samba" DOG = "Bernie" printf "The three dogs are named %s, %s and %s.\n", . . . before the variable name: {{{ sh awk '{var="foo";print var}' }}} === Variable names inside string constants . . . variables, using [[concatenation]]: {{{ awk # print the concatenation of a string and a variable . . . directly print "hello " name; # concatenate, assign to 'newstr' . . .
3K - last updated 2012-04-22 11:42 UTC by unregistered
WartAndWishList
Awk is a wonderful language! That said, there are a few annoying bits... == The Good * well-documented . . . specific escape sequences for strftime and [s]printf) == The Bad * It's quite difficult to map back . . .
7K - last updated 2009-04-13 18:39 UTC by goedel
WhenAreTheFieldsSet
Basically, you should set FS before it may be called upon to split $0 into fields. Once awk encounters . . . in a line. e.g., {{{ awk BEGIN { FS=":" } { print $1 } }}} e.g., {{{ awk -F: '{ print $1 }' }}} . . . if you run code like this {{{ awk { FS=":"; print $1 } }}} on this data: {{{ first:second:third . . . surprisingly, code like {{{ awk { FS=":"; } { print $1; } }}} will also behave in the same way. . . .
1K - last updated 2008-12-15 12:46 UTC by pgas
whitespace
== _Line breaks are best placed at whitespace points_ The [[awk]] extraction and reporting language is . . . split a line at whitespace points /foobar/ \ { print $1 } }}} . . .
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> . . . then easy: {{{ sh awk -F'</?tag>' 'NF>1{print $2}' }}} This can be generalized if you have . . . sh awk -F'</?tag>' '{for(i=2;i<=NF;i++) print $i}' }}} ==== <tag> </tag> different . . . tags so: {{{ sh awk ' /<\/tag>/{f=0} f{print} /<tag>/{f=1}' }}} * The above solutions . . . }}} === Extracting the value of the . . .
2K - last updated 2011-11-23 15:06 UTC by pgas
y0tta
**y0tta:** http://awk.freeshell.org/y0tta revised: 2014-05-30 . . . -v u=\136# -v v=\136-- $0~u{next}$0~v{print;next}/\173{{/,/\175}}/{print;next}{gsub((FS)FS,t);print(($0)s)} . . . \046 & \073 ; \136 ^ \173 { \175 } pclip prints the clipboard; clip copies to clipboard }}} . . .
3K - last updated 2014-05-30 05:06 UTC by g0ph3r
148 pages found.
