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Full Discussion: grep string from a file
Top Forums Shell Programming and Scripting grep string from a file Post 302449599 by jimmy_y on Tuesday 31st of August 2010 03:52:43 AM
Old 08-31-2010
grep string from a file
hi everyone,

1.txt
Code:
12
34
56

2.txt
Code:
456----aa
abc;b;b;b
34;a;a;a;a

output is
Code:
456----aa
34;a;a;a;a

my code is: tmp.txt
Code:
#!/usr/bin/perl
use strict;
use warnings;

my $tmp;
open(FH,'1.txt') or die "$!";
while(<FH>){
        chomp;
        $tmp = `grep "$_" 2.txt`;
        if ($tmp ne '') {
                print "$tmp";
        }
}
close FH;

it works, but the problem you image 1.txt has 30k lines, 2.txt has many many k lines, this script is very low using `grep`.
Please advice, any simple way. Thanks
 

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LEARN ABOUT OPENDARWIN

zgrep

ZGREP(1)						      General Commands Manual							  ZGREP(1)

NAME

       zgrep - search possibly compressed files for a regular expression

SYNOPSIS

       zgrep [ grep_options ] [ -e ] pattern filename...

DESCRIPTION

       Zgrep  is used to invoke the grep on compress'ed or gzip'ed files. All options specified are passed directly to grep.  If no file is speci-
       fied, then the standard input is decompressed if necessary and fed to grep.  Otherwise the given files are uncompressed	if  necessary  and
       fed to grep.

       If  zgrep  is invoked as zegrep or zfgrep then egrep or fgrep is used instead of grep.  If the GREP environment variable is set, zgrep uses
       it as the grep program to be invoked. For example:

	   for sh:  GREP=fgrep	zgrep string files
	   for csh: (setenv GREP fgrep; zgrep string files)

AUTHOR

       Charles Levert (charles@comm.polymtl.ca)

SEE ALSO

       grep(1), egrep(1), fgrep(1), zdiff(1), zmore(1), znew(1), zforce(1), gzip(1), gzexe(1)

																	  ZGREP(1)
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