This demonstrates the basic technique for your needs. You will need to read up on perlfunc:open to find out how to open your files rather than using embedded (inline) files as I am here. You'll also need to look in perlrun and perlop if you want to supply the filenames on the command line rather than hard coding them.

Hope this helps. If you have problems with converting the code to your needs, post your attempt and any errors and we'll try and help you further. 

#! perl -sw
use strict;
use Inline::Files;

my %second = map{ /^(\d+),.*$/; $1 => undef }<SECOND>;

while(<FIRST>) {
    /^(\d+),.*$/;
    print if not exists $second{$1};
}
 exit;
__FIRST__
1524781,Anderson,Jon,srv01,jon,12-05-02.
1843552,Bruford,William,srv01,william,12-17-02.
7589243,Howe,Steven,srv01,steven,12-05-02.
0547629,Squire,Chris,srv01,chris,12-05-02.
5486135,Wakeman,Rick,srv01,rick,12-17-02.
__SECOND__
1524781,Anderson,Jon,srv01,jon,12-05-02.
1843552,Bruford,William,srv01,william,12-17-02.
0547629,Squire,Chris,srv01,chris,12-05-02.

[download]

Gives this output. 

C:\test>215414
7589243,Howe,Steven,srv01,steven,12-05-02.
5486135,Wakeman,Rick,srv01,rick,12-17-02.

C:\test>

[download]

Okay you lot, get your wings on the left, halos on the right. It's one size fits all, and "No!", you can't have a different color.
Pick up your cloud down the end and "Yes" if you get allocated a grey one they are a bit damp under foot, but someone has to get them.
Get used to the wings fast cos its an 8 hour day...unless the Govenor calls for a cyclone or hurricane, in which case 16 hour shifts are mandatory.
Just be grateful that you arrived just as the tornado season finished. Them buggers are real work.

In reply to Re: file comparison by BrowserUk
in thread file comparison by gasky

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.