Maybe not the most elegant solution (and I bet rather slow as well)
It finds the longest string that is at the start of every line in the
imput. 
use warnings;
use strict;

my %ch;
my $part;
my $lines;

while (<DATA>) {
    chomp;
    $part="";
 
    map { $part .= $_;
          print $part."\n";
          $ch{$part}++;
         } split (//);
    $lines ++;
}

my $max;
foreach  (keys (%ch) ) {
    if ( ($ch{$_} == $lines) and (length($_) > length($max)) ) {
        $max = $_;
    }
}

print $max;

__DATA__
abcdefg
abcd
abcd grtf
abcd abd
abcd daf

[download]


si_lence

In reply to Re: identifying arbitury patterns in multiple strings by si_lence
in thread identifying arbitury patterns in multiple strings by westernflame

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