Well, perl makes it pretty easy to handle a task like this, but it's worthwhile pointing out that standard unix/linux utilities do it easily too... 
cut -f1 -d\| input_file | sort | uniq -c

[download]
but in order to get the particular output format you want, a little more work is needed, which is actually easiest to do with perl: 
 ... | perl -pale '$_=join "|",$F[1],$F[0]'

[download]
The "p","a","l" and "e" command-line options are described in the perlrun manual, and "join" is one of the many built-in functions described in perlfunc (and you can go directly to the description of "join" using the command line perldoc -f join.

Please understand that "looking around the web" might not be a good strategy -- especially if you're "looking for a perl program which could handle..." some task for which you don't know the proper search term (e.g. "histogram" or "token frequency"). Look at resources that teach you how to use perl, look at existing code, play with it, break it, and learn to fix it.

In reply to Re: Parse a data file (.txt format), read column and have the count by graff
in thread Parse a data file (.txt format), read column and have the count by jon36

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.