How to insert an array element within regex? Post: 302852177

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Top Forums Shell Programming and Scripting How to insert an array element within regex? Post 302852177 by drl on Tuesday 10th of September 2013 05:24:03 PM

09-10-2013

Registered User

Hi.

Here's an example:

Code:

#!/usr/bin/env bash

# @(#) s2	Demonstrate awk built-in function match(target,re-string).

# Utility functions: print-as-echo, print-line-with-visual-space, debug.
# export PATH="/usr/local/bin:/usr/bin:/bin"
pe() { for _i;do printf "%s" "$_i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
db() { ( printf " db, ";for _i;do printf "%s" "$_i";done;printf "\n" ) >&2 ; }
db() { : ; }
C=$HOME/bin/context && [ -f $C ] && $C awk

FILE=${1-data2}

pl " Input data file $FILE:"
cat $FILE

pl " Results:"
awk --posix '
	BEGIN { re = "ab{2}" }
	{ if ( match($0,re) ) { print " Matched",re,"in",$0; next} }
	{ print " NO match for",re,"in",$0}
' $FILE

exit 0

producing:

Code:

$ ./s2

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 2.6.26-2-amd64, x86_64
Distribution        : Debian GNU/Linux 5.0.8 (lenny) 
bash GNU bash 3.2.39
awk GNU Awk 3.1.5

-----
 Input data file data2:
a
ab
abb
aab
aabbbb

-----
 Results:
 NO match for ab{2} in a
 NO match for ab{2} in ab
 Matched ab{2} in abb
 NO match for ab{2} in aab
 Matched ab{2} in aabbbb

Note that for some special characters in REs, one must use --posix with gawk.

Best wishes ... cheers, drl

drl

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LEARN ABOUT SUNOS

getusershell

getusershell(3C)					   Standard C Library Functions 					  getusershell(3C)

NAME

       getusershell, setusershell, endusershell - get legal user shells

SYNOPSIS

       #include <unistd.h>

       char *getusershell(void);

       void setusershell(void);

       void endusershell(void);

DESCRIPTION

       The  getusershell()  function  returns  a  pointer  to  a  legal  user  shell  as defined by the system manager in the file /etc/shells. If
       /etc/shells does not exist, the following locations of the standard system shells are used in its place:

       /bin/bash		  /bin/csh
       /bin/jsh 		  /bin/ksh
       /bin/pfcsh		  /bin/pfksh
       /bin/pfsh		  /bin/sh
       /bin/tcsh		  /bin/zsh
       /sbin/jsh		  /sbin/pfsh
       /sbin/sh 		  /usr/bin/bash
       /usr/bin/csh		  /usr/bin/jsh
       /usr/bin/ksh		  /usr/bin/pfcsh
       /usr/bin/pfksh		  /usr/bin/pfsh
       /usr/bin/sh		  /usr/bin/tcsh
       /usr/bin/zsh		  /usr/xpg4/bin/sh

       The getusershell() function opens the file /etc/shells, if it exists, and returns the next entry in the list of shells.

       The setusershell() function rewinds the file or the list.

       The endusershell() function closes the file, frees any memory used by getusershell() and setusershell(), and rewinds the file /etc/shells.

RETURN VALUES

       The getusershell() function returns a null pointer on EOF.

BUGS

       All information is contained in memory that may be freed with a call to endusershell(), so it must be copied if it is to be saved.

SunOS 5.10							    30 Aug 2004 						  getusershell(3C)

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