You are reading through the second file as many times as there are lines in the first file. That's way inefficent. Instead, consider reading through the first file and putting its contents into a hash keyed off of the pertinent value. Something like (untested): 
my %file1_row_for;
while (my $input = <THAT_FILE>){
    # only grab column 2
    my ( undef, $id ) = split /;/, $input;
    my $file1_row_for{$id} = $input;
}

[download]
Do something like that for the first file, then you can do something like this: 
while ( my $input = <THAT_OTHER_FILE> ){
    my ( $id2 ) = split /;/, $input;
    print OUTFILE $input
    print OUTFILE ';' . $file1_row_for{$id2} if defined $file1_row_for
+{$id2}
    print OUTFILE "\n";
}

[download]
To generate your output. One other question, though: is there a possibility that there will be more than one matching row in the second file? Even if you think there isn't, you should probably write your code to either process that in a particular manner (output two lines?) or to die if it runs into that scenario. 
perl -e 'split//,q{john hurl, pest caretaker}and(map{print @_[$_]}(joi
+n(q{},map{sprintf(qq{%010u},$_)}(2**2*307*4993,5*101*641*5261,7*59*79
+*36997,13*17*71*45131,3**2*67*89*167*181))=~/\d{2}/g));'

[download]

In reply to Re: concatenation of lines from two different files by agianni
in thread concatenation of lines from two different files by steph_bow

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.