Perl GREP

rajkrishna89 has asked for the wisdom of the Perl Monks concerning the following question:

Im trying to grep a variable which is used in an array to search in files...

if ( grep /$Check /i, <FILE> )
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The check variable contains tags such as 1() 2() 3()

i want to match the whole tag but the following tags are getting grepped 1( 2 3(

I want the grep the whole tag ..i tried the following

 
if ( grep -w "$Check", <FILE> )
if ( grep -o "$Check", <FILE> )
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but its stil not working

Comment on Perl GREP Select or Download Code

Replies are listed 'Best First'.
Re: Perl GREP by Corion (Patriarch) on Jan 03, 2012 at 15:47 UTC
Where in grep did you find the usage of `grep -w "..."` documented? Maybe you can show us a reduced version of your program, no longer than 15 lines, that still shows the problem? What is the value of `$Check`? What are three representative lines in `FILE`?	[reply] [d/l] [select]
Re: Perl GREP by runrig (Abbot) on Jan 03, 2012 at 15:51 UTC
Parenthesis are regex meta characters and need to be escaped. You can easily do that with the quotemeta function or the "\Q" regex sequence: `my $Check = quotemeta("1()"); if (grep /$Check/i, <FILE>) { ...` [download] That said, I hope the file is small, because slurping the entire contents of a file into memory is usually not a good strategy.	[reply] [d/l]
Re: Perl GREP by kennethk (Abbot) on Jan 03, 2012 at 15:52 UTC
If your variable contains metacharacters, you will need to escape them when you interpolate -- see Quoting metacharacters. Perhaps something like `if ( grep /\Q$Check \E/i, <FILE> )` does what you mean?	[reply] [d/l]