Hi try this simple

use strict;
use diagnostics;

my $line = 'some_for($var)'; #don't match
$line = '    for($var)'; #match
$line = 'for($var)'; #match


if($line =~ m#^(\s+)?for\(#si) {
    print "Match";
}
else {
    print "Non-match";
}
[download]

Gubendran.L