One approach would be to look at every line of the file and inspect that that line matches. A Perl program to inspect a certain line of a file would be:

use strict;
use Tie::File;

my $f = shift;
my $l = shift -1;

tie my @f => 'Tie::File' => $f;
print "$l: $f[$l]";

[download]

Save that program as a file and then invoke it for every line:

perl -w gfarhat.pl testfile.txt 1
perl -w gfarhat.pl testfile.txt 2
...
perl -w gfarhat.pl testfile.txt 9998

[download]

You can golf the above program into the following, if the overhead of creating a Perl program is too much for you:

perl -nle 'BEGIN{$l=pop}print if $.==$l' testfile.txt 1

[download]

In reply to Re: string format validation by Corion
in thread string format validation by gfarhat

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.