Changes

25,326 bytes added , 08:53, 25 September 2018

no edit summary

~~# http://www.catonmat.net~~== Examples ==; get first column from mw table data awk '/~~blog/awk-one~~\|-~~liners-explained-part-one~~/~~# http:~~{getline;print}' /tmp/~~www.catonmat~~terror.~~net~~txt | sed s/~~blog~~\|/~~awk-one-liners-explained-part-two~~/~~# http:~~| sed s/'^ *'/~~www.catonmat.net/blog~~/| sort -u ; see who's trying to SSH into your server (brute force attack) awk~~-one-liners-explained-part-three~~'/~~# http:~~Invalid user/{print $8}' /~~www.catonmat.net~~var/~~blog~~log/~~update~~auth.log | sort | uniq -~~on-famous-awk-one-liners-explained/~~c == Docs ==~~# http://www~~The man page for Awk is 27 pages long.~~catonmat~~ Hard to read in a terminal.~~net/download/awk.cheat.sheet~~ Here is [[File:Awk.pdf|a PDF copy of the Awk manual|thumb]] a PDF copy of the Awk manual

== One-liners ==

<pre>

HANDY ONE-LINERS FOR AWK 22 July 2003

compiled by Eric Pement <pemente@northpark.edu> version 0.22

Latest version of this file is usually at: http://www.student.northpark.edu/pemente/awk/awk1line.txt

USAGE:

Unix: awk '/pattern/ {print "$1"}' # standard Unix shells DOS/Win: awk '/pattern/ {print "$1"}' # okay for DJGPP compiled awk "/pattern/ {print \"$1\"}" # required for Mingw32

Most of my experience comes from version of GNU awk (gawk) compiled for

FILE SPACING:

# double space a file awk '1;{print ""}' awk 'BEGIN{ORS="\n\n"};1'

# double space a file which already has blank lines in it. Output file # should contain no more than one blank line between lines of text. # NOTE: On Unix systems, DOS lines which have only CRLF (\r\n) are # often treated as non-blank, and thus 'NF' alone will return TRUE. awk 'NF{print $0 "\n"}'

# triple space a file awk '1;{print "\n"}'

NUMBERING AND CALCULATIONS:

# precede each line by its line number FOR THAT FILE (left alignment). # Using a tab (\t) instead of space will preserve margins. awk '{print FNR "\t" $0}' files*

# precede each line by its line number FOR ALL FILES TOGETHER, with tab. awk '{print NR "\t" $0}' files*

# number each line of a file (number on left, right-aligned) # Double the percent signs if typing from the DOS command prompt. awk '{printf("%5d : %s\n", NR,$0)}'

# number each line of file, but only print numbers if line is not blank # Remember caveats about Unix treatment of \r (mentioned above) awk 'NF{$0=++a " :" $0};{print}' awk '{print (NF? ++a " :" :"") $0}'

# count lines (emulates "wc -l") awk 'END{print NR}'

# print the sums of the fields of every line awk '{s=0; for (i=1; i<=NF; i++) s=s+$i; print s}'

# add all fields in all lines and print the sum awk '{for (i=1; i<=NF; i++) s=s+$i}; END{print s}'

# print every line after replacing each field with its absolute value awk '{for (i=1; i<=NF; i++) if ($i < 0) $i = -$i; print }' awk '{for (i=1; i<=NF; i++) $i = ($i < 0) ? -$i : $i; print }'

# print the total number of fields ("words") in all lines awk '{ total = total + NF }; END {print total}' file

# print the total number of lines that contain "Beth" awk '/Beth/{n++}; END {print n+0}' file

# print the largest first field and the line that contains it # Intended for finding the longest string in field #1 awk '$1 > max {max=$1; maxline=$0}; END{ print max, maxline}'

# print the number of fields in each line, followed by the line awk '{ print NF ":" $0 } '

# print the last field of each line awk '{ print $NF }'

# print the last field of the last line awk '{ field = $NF }; END{ print field }'

# print every line with more than 4 fields awk 'NF > 4'

# print every line where the value of the last field is > 4 awk '$NF > 4'

TEXT CONVERSION AND SUBSTITUTION:

# IN UNIX ENVIRONMENT: convert DOS newlines (CR/LF) to Unix format awk '{sub(/\r$/,"");print}' # assumes EACH line ends with Ctrl-M

# IN UNIX ENVIRONMENT: convert Unix newlines (LF) to DOS format awk '{sub(/$/,"\r");print}

# IN DOS ENVIRONMENT: convert Unix newlines (LF) to DOS format awk 1

# IN DOS ENVIRONMENT: convert DOS newlines (CR/LF) to Unix format # Cannot be done with DOS versions of awk, other than gawk: gawk -v BINMODE="w" '1' infile >outfile

# Use "tr" instead. tr -d \r <infile >outfile # GNU tr version 1.22 or higher

# delete leading whitespace (spaces, tabs) from front of each line # aligns all text flush left awk '{sub(/^[ \t]+/, ""); print}'

# delete trailing whitespace (spaces, tabs) from end of each line awk '{sub(/[ \t]+$/, "");print}'

# delete BOTH leading and trailing whitespace from each line awk '{gsub(/^[ \t]+|[ \t]+$/,"");print}' awk '{$1=$1;print}' # also removes extra space between fields# This awk idiom can be used to turn command output into spreadsheet-friendly output by separating it with tabs.# So for example, the output of the ls command: ls -l | awk -v OFS="\t" '$1=$1'

# insert 5 blank spaces at beginning of each line (make page offset) awk '{sub(/^/, " ");print}'

# align all text flush right on a 79-column width awk '{printf "%79s\n", $0}' file*

# center all text on a 79-character width awk '{l=length();s=int((79-l)/2); printf "%"(s+l)"s\n",$0}' file*

# substitute (find and replace) "foo" with "bar" on each line awk '{sub(/foo/,"bar");print}' # replaces only 1st instance gawk '{$0=gensub(/foo/,"bar",4);print}' # replaces only 4th instance awk '{gsub(/foo/,"bar");print}' # replaces ALL instances in a line

# substitute "foo" with "bar" ONLY for lines which contain "baz" awk '/baz/{gsub(/foo/, "bar")};{print}'

# substitute "foo" with "bar" EXCEPT for lines which contain "baz" awk '!/baz/{gsub(/foo/, "bar")};{print}'

# change "scarlet" or "ruby" or "puce" to "red" awk '{gsub(/scarlet|ruby|puce/, "red"); print}'

# reverse order of lines (emulates "tac") awk '{a[i++]=$0} END {for (j=i-1; j>=0;) print a[j--] }' file*

# if a line ends with a backslash, append the next line to it # (fails if there are multiple lines ending with backslash...) awk '/\\$/ {sub(/\\$/,""); getline t; print $0 t; next}; 1' file*

# print and sort the login names of all users awk -F ":" '{ print $1 | "sort" }' /etc/passwd

# print the first 2 fields, in opposite order, of every line awk '{print $2, $1}' file

# switch the first 2 fields of every line awk '{temp = $1; $1 = $2; $2 = temp}' file

# print every line, deleting the second field of that line awk '{ $2 = ""; print }'

# print in reverse order the fields of every line awk '{for (i=NF; i>0; i--) printf("%s ",i);printf ("\n")}' file

# remove duplicate, consecutive lines (emulates "uniq") awk 'a !~ $0; {a=$0}'

# remove duplicate, nonconsecutive lines awk '! a[$0]++' # most concise script awk '!($0 in a) {a[$0];print}' # most efficient script

# concatenate every 5 lines of input, using a comma separator # between fields awk 'ORS=%NR%5?",":"\n"' file

SELECTIVE PRINTING OF CERTAIN LINES:

# print first 10 lines of file (emulates behavior of "head") awk 'NR < 11'

# print first line of file (emulates "head -1") awk 'NR>1{exit};1'

# print the last 2 lines of a file (emulates "tail -2") awk '{y=x "\n" $0; x=$0};END{print y}'

# print the last line of a file (emulates "tail -1") awk 'END{print}'

# print only lines which match regular expression (emulates "grep") awk '/regex/'

# print only lines which do NOT match regex (emulates "grep -v") awk '!/regex/'

# print the line immediately before a regex, but not the line # containing the regex awk '/regex/{print x};{x=$0}' awk '/regex/{print (x=="" ? "match on line 1" : x)};{x=$0}'

# print the line immediately after a regex, but not the line # containing the regex awk '/regex/{getline;print}'# someone said somewhere that getline can pose problems.... dunno exactly what/why but here's an alternate# This prints the 5th field of the line following the regex# Then pipes it to grep with perl-compatible regex to use look-behind and look-ahead assertions to print the contents inside parenthesis# so given an error log that contains the following two lines (repeatedly), and you want to extract the names of the tables# Operation failed with exitcode 3# 12:09:54 AM Dumping wordpress (log_civicrm_extension)awk 'f{print $5;f=0} /Operation failed with exitcode/{f=1}' /tmp/mysqldump.error.log | sort | grep -P -o '(?<=$).*(?=$)'## Admittedly this is more complex than just a couple greps!!# grep -A1 /Operation failed with exitcode/ /tmp/mysqldump.error.log | sort | grep -P -o '(?<=$).*(?=$)'

# grep for AAA and BBB and CCC (in any order) awk '/AAA/; /BBB/; /CCC/'

# grep for AAA and BBB and CCC (in that order) awk '/AAA.*BBB.*CCC/'

# print only lines of 65 characters or longer awk 'length > 64'

# print only lines of less than 65 characters awk 'length < 64'

# print section of file from regular expression to end of file awk '/regex/,0' awk '/regex/,EOF'

# print section of file based on line numbers (lines 8-12, inclusive) awk 'NR==8,NR==12'

# print line number 52 awk 'NR==52' awk 'NR==52 {print;exit}' # more efficient on large files

# print section of file between two regular expressions (inclusive) awk '/Iowa/,/Montana/' # case sensitive

SELECTIVE DELETION OF CERTAIN LINES:

# delete ALL blank lines from a file (same as "grep '.' ") awk NF awk '/./'

"sed & awk, 2nd Edition," by Dale Dougherty and Arnold Robbins

O'Reilly, 1997

"UNIX Text Processing," by Dale Dougherty and Tim O'Reilly

Hayden Books, 1987

"Effective awk Programming, 3rd Edition." by Arnold Robbins

O'Reilly, 2001

To fully exploit the power of awk, one must understand "regular

expressions." For detailed discussion of regular expressions, see

"Mastering Regular Expressions, 2d edition" by Jeffrey Friedl

(O'Reilly, 2002).

The manual ("man") pages on Unix systems may be helpful (try "man awk",

#---end of file---

</pre>

== Explained ==

# http://www.catonmat.net/blog/awk-one-liners-explained-part-one/

# http://www.catonmat.net/blog/awk-one-liners-explained-part-two/

# http://www.catonmat.net/blog/awk-one-liners-explained-part-three/

# http://www.catonmat.net/blog/update-on-famous-awk-one-liners-explained/

# http://www.catonmat.net/download/awk.cheat.sheet.pdf

== Cheatsheet ==

http://www.catonmat.net/blog/wp-content/plugins/wp-downloadMonitor/user_uploads/awk.cheat.sheet.pdf

<center>'''''AWK ([[wp:Alfred_Aho|Aho]], [[wp:Peter_J._Weinberger|Weinberger]], & [[wp:Brian_Kernighan|Kernighan]]) Summary'''''</center>

'''Predefined Variable Summary:'''

{|

| |

| | <center>'''Support:'''</center>

|-

| | Variable

| | Description

| | '''AWK'''

| | '''NAWK'''

| | '''GAWK'''

|-

| |

|-

| | '''FS'''

| | Input '''F'''ield '''S'''eparator, a space by default.

| | <center>'''Y'''</center>

|-

| | '''OFS'''

| | '''O'''utput '''F'''ield '''S'''eparator, a space by default.

| | <center>'''Y'''</center>

|-

| | ''' NF '''

| | The '''N'''umber of '''F'''ields in the current input record.

| | <center>'''Y'''</center>

|-

| | ''' NR '''

| | The total '''N'''umber of input '''R'''ecords seen so far.

| | <center>'''Y'''</center>

|-

| | ''' RS '''

| | '''R'''ecord '''S'''eparator, a newline by default.

| | <center>'''Y'''</center>

|-

| | ''' ORS '''

| | '''O'''utput '''R'''ecord '''S'''eparator, a newline by default.

| | <center>'''Y'''</center>

|-

| | ''' FILENAME '''

| | The name of the current input file. If no files are specified on the command line, the value of '''FILENAME''' is "-". However, '''FILENAME''' is undefined inside the '''BEGIN''' block (unless set by '''''getline''''').

| | <center>'''Y'''</center>

|-

| | ''' ARGC '''

| | The number of command line arguments (does not include options to gawk, or the program source). Dynamically changing the contents of '''ARGV''' control the files used for data.

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | ''' ARGV '''

| | Array of command line arguments. The array is indexed from 0 to '''ARGC''' - 1.

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''ARGIND'''

| | The index in '''ARGV''' of the current file being processed.

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''BINMODE'''

| | On non-POSIX systems, specifies use of "binary" mode for all file I/O.Numeric values of 1, 2, or 3, specify that input files, output files, or all files, respectively, should use binary I/O. String values of "r", or "w" specify that input files, or output files, respectively, should use binary I/O. String values of "rw" or "wr" specify that all files should use binary I/O. Any other string value is treated as "rw", but generates a warning message.

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''CONVFMT'''

| | The '''CONVFMT''' variable is used to specify the format when converting a number to a string. Default: "%.6g"

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''ENVIRON'''

| | An array containing the values of the current environment.

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''ERRNO'''

| | If a system error occurs either doing a redirection for '''getline''', during a read for '''''getline''''', or during a '''close()''', then '''ERRNO''' will contain a string describing the error. The value is subject to translation in non-English locales.

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''FIELDWIDTHS'''

| | A white-space separated list of fieldwidths. When set, ''gawk'' parses the input into fields of fixed width, instead of using the value of the '''FS''' variable as the field separator.

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''FNR'''

| | Contains number of lines read, but is reset for each file read.

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''IGNORECASE'''

| | Controls the case-sensitivity of all regular expression and string operations. If '''IGNORECASE''' has a non-zero value, then string comparisons and pattern matching in rules, field splitting with '''FS''', record separating with RS, regular expression matching with '''~''' and '''!~''', and the '''gensub()''', '''gsub()''', '''index()''', '''match()''', '''split()''', and '''sub()''' built-in functions all ignore case when doing regular expression operations. NOTE: Array subscripting is not affected. However, the '''asort()''' and '''asorti()''' functions are affected.

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''LINT'''

| | Provides dynamic control of the '''--lint''' option from within an AWK program. When true, ''gawk'' prints lint warnings.

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''OFMT'''

| | The default output format for numbers. Default: "%.6g"

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''PROCINFO'''

| | The elements of this array provide access to information about the running AWK program.

PROCINFO["egid"]the value of the getegid(2) system call.

PROCINFO["euid"]the value of the geteuid(2) system call.

PROCINFO["FS"]"'''FS'''" if field splitting with FS is in effect,or "'''FIELDWIDTHS'''" if field splitting with'''FIELDWIDTHS''' is in effect.

PROCINFO["gid"]the value of the getgid(2) system call.

PROCINFO["pgrpid"]the process group ID of the current process.

PROCINFO["pid"]the process ID of the current process.

PROCINFO["ppid"]the parent process ID of the current process.

PROCINFO["uid"]the value of the getuid(2) system call.

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''RT'''

| | The record terminator. Gawk sets '''RT''' to the input text that matched the character or regular expression specified by '''RS'''.

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''RSTART'''

| | The index of the first character matched by '''match()'''<nowiki>; 0 if no match.</nowiki>

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''RLENGTH'''

| | The length of the string matched by '''match();''' -1 if no match.

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''SUBSEP'''

| | The character used to separate multiple subscripts in array elements.Default: "\034" (non-printable character, dec: 28, hex: 1C)

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|-

| | '''TEXTDOMAIN'''

| | The text domain of the AWK program; used to find the localized translations for the program's strings.

| | <center>'''N'''</center>

| | <center>'''Y'''</center>

|}

'''� 2007 Peteris Krumins peter@catonmat.net[http://www.catonmat.net/ http://www.catonmat.net] good coders code, great reuse'''

Variable is supported:'''Y'''

Variable is not supported:'''N'''

'''Command line argument summary:'''

{|

| | '''Argument'''

| | '''Description'''

|-

| |

|-

| | '''-F fs--field-sepearator fs'''

| | Use '''''fs''''' for the input field separator (the value of the '''FS''' predefined variable).

|-

| | '''-v var=val--assign var=val'''

| | Assign the value '''''val''''' to the variable '''''var''''', before execution of the program begins. Such variable values are available to the '''BEGIN''' block of an ''AWK'' program.

|-

| | '''-f program-file--file program-file'''

| | Read the AWK program source from the file program-file, instead of from the first command line argument. Multiple -f (or --file) options may be used.

|-

| | '''-mf NNN-mr NNN'''

| | Set various memory limits to the value '''NNN'''. The '''f''' flag sets the maximum number of fields, and the r flag sets the maximum record size. (Ignored by ''gawk'', since ''gawk'' has no pre-defined limits)

|-

| | '''-W compat'''

'''-W traditional'''

'''--compat'''

'''--traditional'''

| | Run in compatibility mode. In compatibility mode, ''gawk'' behaves identically to UNIX ''awk''<nowiki>; none of the GNU-specific extensions are recognized.</nowiki>

|-

| | '''-W copyleft'''

'''-W copyright'''

'''--copyleft'''

'''--copyright'''

| | Print the short version of the GNU copyright information message on the standard output and exit successfully.

|-

| | '''-W dump-variables[=file]--dump-variables[=file]'''

| | Print a sorted list of global variables, their types and final values to '''''file'''''. If no '''''file''''' is provided, gawk uses a file named awkvars.out in the current directory.

|-

| | '''-W help'''

'''-W usage'''

'''--help'''

'''--usage'''

| | Print a relatively short summary of the available options on the standard output.

|-

| | '''-W lint[=value]--lint[=value]'''

| | Provide warnings about constructs that are dubious or non-portable to other AWK impl�s. With argument '''fatal''', lint warnings become fatal errors. With an optional argument of '''invalid''', only warnings about things that are actually invalid are issued. (This is not fully implemented yet.)

|-

| | '''-W lint-old--lint-old'''

| | Provide warnings about constructs that are not portable to the original version of Unix ''awk''.

|-

| | '''-W gen-po--gen-po'''

| | Scan and parse the AWK program, and generate a GNU .po format file on standard output with entries for all localizable strings in the program. The program itself is not executed.

|-

| | '''-W non-decimal-data--non-decimal-data'''

| | Recognize octal and hexadecimal values in input data.

|-

| | '''-W posix--posix'''

| | This turns on compatibility mode, with the following additional restrictions:

* \x escape sequences are not recognized.

* Only space and tab act as field separators when '''FS''' is set to a single space, new-line does not.

* You cannot continue lines after ? and :.

* The synonym func for the keyword function is not recognized.

* The operators ** and **= cannot be used in place of ^ and ^=.

* The '''''fflush()''''' function is not available.

|-

| | '''-W profile[=prof_file]--profile[=prof_file]'''

| | Send profiling data to '''''prof_file'''''. The default is awkprof.out. When run with ''gawk'', the profile is just a "pretty printed" version of the program. When run with ''pgawk'', the profile contains execution counts of each statement in the program in the left margin and function call counts for each user-defined function.

|-

| | '''-W re-interval--re-interval'''

| | Enable the use of interval expressions in regular expression matching. Interval expressions were not traditionally available in the AWK language.

|-

| | '''-W source program-text--source program-text'''

| | Use '''''program-text''''' as AWK program source code. This option allows the easy intermixing of library functions (used via the '''-f''' and '''--file''' options) with source code entered on the command line.

|-

| | '''-W version--version'''

| | Print version information for this particular copy of ''gawk'' on the standard output.

|-

| | '''--'''

| | Signal the end of options. This is useful to allow further arguments to the AWK program itself to start with a "-". This is mainly for consistency with the argument parsing convention used by most other POSIX programs.

|}

'''� 2007 Peteris Krumins peter@catonmat.net[http://www.catonmat.net/ http://www.catonmat.net] good coders code, great reuse'''

'''Statements and Functions:'''

{|

| | '''I/O Statements'''

| | '''Description'''

|-

| |

|-

| | '''close(''file'' [, ''how''])'''

| | Close file, pipe or co-process. The optional how should only be used when closing one end of a two-way pipe to a co-process. It must be a string value, either "to" or "from".

|-

| | '''getline'''

| | Set $0 from next input record; set NF, NR, FNR. Returns 0 on EOF and �1 on an error. Upon an error, ERRNO contains a string describing the problem.

|-

| | '''getline <''file'''''

| | Set $0 from next record of file; set NF.

|-

| | '''getline ''var'''''

| | Set var from next input record; set NR, FNR.

|-

| | '''getline <u>''var''</u> <''file'''''

| | Set var from next record of file.

|-

| | '''command | getline [''var'']'''

| | Run command piping the output either into $0 or var, as above. If using a pipe or co-process to getline, or from print or printf within a loop, you must use close() to create new instances

|-

| | '''command |& getline [''var'']'''

| | Run command as a co-process piping the output either into $0 or var, as above. Co-processes are a gawk extension.

|-

| | '''next'''

| | Stop processing the current input record. The next input record is read and processing starts over with the first pattern in the AWK program. If the end of the input data is reached, the END block(s), if any, are executed.

|-

| | '''nextfile'''

| | Stop processing the current input file. The next input record read comes from the next input file. FILENAME and ARGIND are updated, FNR is reset to 1, and processing starts over with the first pattern in the AWK program. If the end of the input data is reached, the END block(s), are executed.

|-

| | '''print'''

| | Prints the current record. The output record is terminated with the value of the ORS variable.

|-

| | '''print ''expr-list'''''

| | Prints expressions. Each expression is separated by the value of the OFS variable. The output record is terminated with the value of the ORS variable.

|-

| | '''print ''expr-list'' >''file'''''

| | Prints expressions on file. Each expression is separated by the value of the OFS variable. The output record is terminated with the value of the ORS variable.

|-

| | '''printf ''fmt'', ''expr-list'''''

| | Format and print.

|-

| | '''printf ''fmt'', ''expr-list'' >''file'''''

| | Format and print on file.

|-

| | '''system(''cmd-line'')'''

| | Execute the command cmd-line, and return the exit status.

|-

| | '''fflush([''file''])'''

| | Flush any buffers associated with the open output file or pipe file. If file is missing, then stdout is flushed. If file is the null string, then all open output files and pipes have their buffers flushed.

|-

| | '''print ... >> file'''

| | appends output to the file.

|-

| | '''print ... | command'''

| | writes on a pipe.

|-

| | '''print ... |& command'''

| | sends data to a co-process.

|}

{|

| | '''Numeric Functions'''

| | '''Description'''

|-

| |

|-

| | '''atan2(''y, x'')'''

| | Returns the arctangent of y/x in radians.

|-

| | '''cos(''expr'')'''

| | Returns the cosine of expr, which is in radians.

|-

| | '''exp(''expr'')'''

| | The exponential function.

|-

| | '''int(''expr'')'''

| | Truncates to integer.

|-

| | '''log(''expr'')'''

| | The natural logarithm function.

|-

| | '''rand()'''

| | Returns a random number N, between 0 and 1, such that 0 <= N < 1.

|-

| | '''sin(''expr'')'''

| | Returns the sine of expr, which is in radians.

|-

| | '''sqrt(''expr'')'''

| | The square root function.

|-

| | '''srand([''expr''])'''

| | Uses expr as a new seed for the random number generator. If no expr is provided, the time of day is used. The return value is the previous seed for the random number generator.

|}

{|

| | '''Bit Manipulations Functions'''

| | '''Description'''

|-

| |

|-

| | '''and(''v1'', ''v2'')'''

| | Return the bitwise AND of the values provided by v1 and v2.

|-

| | '''compl(''val'')'''

| | Return the bitwise complement of val.

|-

| | '''lshift(''val'', ''count'')'''

| | Return the value of val, shifted left by count bits.

|-

| | '''or(''v1'', ''v2'')'''

| | Return the bitwise OR of the values provided by v1 and v2.

|-

| | '''rshift(''val'', ''count'')'''

| | Return the value of val, shifted right by count bits.

|-

| | '''xor(''v1'', ''v2'')'''

| | Return the bitwise XOR of the values provided by v1 and v2.

|}

{|

| colspan="2" | '''I18N functions'''

|-

| |

|-

| colspan="2" | '''bindtextdomain(directory [, domain])'''

|-

| colspan="2" | '''Specifies the directory where gawk looks for the .mo files. It returns the directory where domain is ``bound.'' The default domain is the value of TEXTDOMAIN. If directory is the null string (""), then bindtextdomain() returns the current binding for the given domain.'''

|-

| colspan="2" | '''dcgettext(string [, domain [, category]])'''

|-

| colspan="2" | '''Returns the translation of string in text domain domain for locale category category. The default value for domain is the current value of TEXTDOMAIN. The default value for category is "LC_MESSAGES". If you supply a value for category, it must be a string equal to one of the known locale categories. You must also supply a text domain. Use TEXTDOMAIN if you want to use the current domain.'''

|-

| colspan="2" | '''dcngettext(string1 , string2 , number [, domain [, category]])'''

|-

| colspan="2" | '''Returns the plural form used for number of the translation of string1 and string2 in text domain domain for locale category category. The default value for domain is the current value of TEXTDOMAIN. The default value for category is "LC_MESSAGES". If you supply a value for category, it must be a string equal to one of the known locale categories. You must also supply a text domain. Use TEXTDOMAIN if you want to use the current domain.'''

|}

{|

| | '''String Functions'''

| | '''Description'''

|-

| |

|-

| | '''asort(''s'' [, ''d'']) '''

| | Returns the number of elements in the source array s. The contents of s are sorted using gawk's normal rules for comparing values, and the indexes of the sorted values of s are replaced with sequential integers starting with 1. If the optional destination array d is specified, then s is first duplicated into d, and then d is sorted, leaving the indexes of the source array s unchanged.

|-

| | '''asorti(''s'' [, ''d''])'''

| | Returns the number of elements in the source array s. The behavior is the same as that of asort(), except that the array indices are used for sorting, not the array values. When done, the array is indexed numerically, and the values are those of the original indices. The original values are lost; thus provide a second array if you wish to preserve the original.

|-

| | '''gensub(''r'', ''s'', ''h'' [, ''t''])'''

| | Search the target string t for matches of the regular expression r. If h is a string beginning with g or G, then replace all matches of r with s. Otherwise, h is a number indicating which match of r to replace. If t is not supplied, $0 is used instead. Within the replacement text s, the sequence \n, where n is a digit from 1 to 9, may be used to indicate just the text that matched the n'th parenthesized subexpression. The sequence \0 represents the entire matched text, as does the character &. Unlike sub() and gsub(), the modified string is returned as the result of the function, and the original target string is not changed.

|-

| | '''gsub(''r'', ''s'' [, ''t''])'''

| | For each substring matching the regular expression r in the string t, substitute the string s, and return the number of substitutions. If t is not supplied, use $0. An & in the replacement text is replaced with the text that was actually matched. Use \& to get a literal &. (This must be typed as "\\&")

|-

| | '''index(''s'', ''t'')'''

| | Returns the index of the string t in the string s, or 0 if t is not present. (This implies that character

'''indices start at one.)'''

|-

| | '''length([''s''])'''

| | Returns the length of the string s, or the length of $0 if s is not supplied.

|-

| | '''match(''s'', ''r'' [, ''a''])'''

| | Returns the position in s where the regular expression r occurs, or 0 if r is not present, and sets the values of RSTART and RLENGTH. Note that the argument order is the same as for the ~ operator: str ~ re. If array a is provided, a is cleared and then elements 1 through n are filled with the portions of s that match the corresponding parenthesized subexpression in r. The 0'th element of a contains the portion of s matched by the entire regular expression r. Subscripts a[n, "start"], and a[n, "length"] provide the starting index in the string and length respectively, of each matching substring.

|-

| | '''split(''s'', ''a'' [, ''r''])'''

| | Splits the string s into the array a on the regular expression r, and returns the number of fields. If r is omitted, FS is used instead. The array a is cleared first. Splitting behaves identically to field splitting.

|-

| | '''sprintf(''fmt'', ''expr-list'')'''

| | Prints expr-list according to fmt, and returns the resulting string.

|-

| | '''strtonum(''str'')'''

| | Examines str, and returns its numeric value. If str begins with a leading 0, strtonum() assumes that str is an octal number. If str begins with a leading 0x or 0X, strtonum() assumes that str is a hexadecimal number.

|-

| | '''sub(''r'', ''s'' [, ''t''])'''

| | Just like gsub(), but only the first matching substring is replaced.

|-

| | '''substr(''s'', ''i'' [, ''n''])'''

| | Returns the at most n-character substring of s starting at i. If n is omitted, the rest of s is used.

|-

| | '''tolower(''str'')'''

| | Returns a copy of the string str, with all the upper-case characters in str translated to their corresponding lower-case counterparts. Non-alphabetic characters are left unchanged.

|-

| | '''toupper(''str'')'''

| | Returns a copy of the string str, with all the lower-case characters in str translated to their corresponding upper-case counterparts. Non-alphabetic characters are left unchanged.

|}

{|

| | '''Time Functions'''

| | '''Description'''

|-

| |

|-

| | '''mktime(''datespec'')'''

| | Turns datespec into a time stamp of the same form as returned by systime(). The datespec is a string of the form YYYY MM DD HH MM SS[ DST]. The contents of the string are six or seven numbers representing respectively the full year including century, the month from 1 to 12, the day of the month from 1 to 31, the hour of the day from 0 to 23, the minute from 0 to 59, and the second from 0 to 60, and an optional daylight saving flag. The values of these numbers need not be within the ranges specified; for example, an hour of -1 means 1 hour before midnight. The origin-zero Gregorian calendar is assumed, with year 0 preceding year 1 and year -1 preceding year 0. The time is assumed to be in the local timezone. If the daylight saving flag is positive, the time is assumed to be daylight saving time; if zero, the time is assumed to be standard time; and if negative (the default), mktime() attempts to determine whether daylight saving time is in effect for the specified time. If datespec does not contain enough elements or if the resulting time is out of range, mktime() returns -1.

|-

| | '''strftime([''format'' [, ''timestamp'']])'''

| | Formats timestamp according to the specification in format. The timestamp should be of the same form as returned by systime(). If timestamp is missing, the current time of day is used.If format is missing, a default format equivalent to the output of date(1) is used. See the specification for the strftime() function in ANSI C for the format conversions that are guaranteed to be available. A public-domain version of strftime(3) and a man page for it come with gawk; if that version was used to build gawk, then all of the conversions described in that man page are available to gawk.

|-

| | '''systime()'''

| | Returns the current time of day as the number of seconds since the Epoch (1970-01-01 00:00:00 UTC on POSIX systems).

|}

[[Category:System Administration]]

[[Category:Development]]

[[Category:Bash]]

Freephile

Bureaucrats, confirmed, Administrators

4,558

edits

Changes

Awk (view source)

Revision as of 08:53, 25 September 2018