UPDATE: As CountZero points out below, there is a problem with my do {...} blocks, so please check his proposal Re: matching datetimestamps and concatenating data where timestamps match from multiple large datafiles which should run as intended.

It sounds like your data is sorted ascending with respect to time. Under this assumption I propose to use the following idea of a script: 

use strict;
use warnings;

open my $fileA, ... or die;
open my $fileB, ... or die;
# same with the other files

my $lineB = '';
while( my $lineA = <$fileA> ) {
  chomp $lineA;
  next unless $lineA =~ m/^\d\.+(\d{2}):(\d{2}):(\d{2})\.+(\d{2})(\d{2
+})(\d{2})\d{2}.abc/;  
  my $dateA = ... ; # construct date from $1, $2 etc
  do {
    chomp $lineB;
    next unless $lineB =~ m/^\d\.+(\d{2}):(\d{2}):(\d{2})\.+(\d{2})(\d
+{2})(\d{2})\d{2}.abc/;  
    my $dateB = ... ; # construct date ...
    next if $dateB < $dateA; # use some date and time library for thes
+e comparisons
    last if $dateB > $dateA; # ...
    $lineA .= $lineB;
  } while( $lineB = <$fileB> );
  # same with fileC etc...
  print "$lineA\n";
}

[download]

In reply to Re: matching datetimestamps and concatenating data where timestamps match from multiple large datafiles by hdb
in thread matching datetimestamps and concatenating data where timestamps match from multiple large datafiles by Cosmic37

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.