#! /usr/bin/perl

use strict;
use warnings;
use Tie::File;

my $file = 'test.txt';
tie my @array,'Tie::File',$file or die $!;
foreach my $line(@array){
  $line =~ s~\$res = system("/prj/sw/tool")~\$res = system("/prj/vlsit
+/toolsmodule")~;
}
untie @array;
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You try this,

open (FIN, "test.txt")|| die ("test.txt does not exists");
undef $/;
$instr = <FIN>;
$instr =~ s|/prj/sw/tool|/prj/vlsi/toolsmodule|si;
print "$instr";
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hi prasad is your solution takes in to consideration that there are many other lines , other than what i want to replace. Thanks sachinc

sachin chat,

$/ is a input record separator, when you read a content in the file, it will undef the newline characters("\n") in the file if we use undef $/;. (default value of input record separator is "\n")

$instr will take all the contents in the file (not first line alone).

is your solution takes in to consideration that there are many other lines

yes, if there is also only one line, you will get the correct output.

Prasad

perl -pi 's{\Qsystem("/prj/sw/tool")}{system("/prj/vlsi/toolsmodule")}
+' test.txt
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perl -pi -e 's!/prj/sw/tool!/prj/vlsi/toolsmodule!;' test.txt
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