Here is my outline:

  1. Read one file and split into first element and rest. Create hash with key being the first element.
  2. Read second file line by line. Split into first element and rest.
  3. See whether first element exists in hash. If so print all.
Not tested as i do not have two fitting files at hand. 

use strict; 
use warnings; 

open (my $fh, "<", "C:/position.txt"); 
my %position = map { split /\t/, $_, 2 } <$fh>; # not sure about this
close($fh); 

open (my $file, "<", "C:/platform.txt"); 
open (my $newfile, ">", "C:/result.txt"); 
foreach my $line (<$file>) { 
  my( $start, $rest ) = split /\t/, $line, 2; 
  print $newfile $start, "\t", $position{$start},"\t", $line if exists
+ $position{$start};
} 
close($file); 
print "DONE";

[download]

In reply to Re: match text files by hdb
in thread match text files by Salwrwr

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.