The following is ok for reasonable size files but may bog down when things get huge.

use strict;
use warnings;
use Data::Dump::Streamer;

my %firstLines;
my @lines;

while (<DATA>) {
    chomp;
    my ($data, $type) = /(.*)\s+TYPE:\s+(\w+)$/;
    
    next if ! defined $type; # ignore malformed line
    if (exists $firstLines{$data}) {
        $lines[$firstLines{$data}] .= ", $type";
    } else {
        $firstLines{$data} = @lines;
        push @lines, $_;
    }
}

print join "\n", @lines;

__DATA__
MCAT: 0xf30cbe01 PCAT: 0xcda2b409 LMAT: 0x00100000 TYPE: KA0
MCAT: 0xcc3fbed1 PCAT: 0x000fb109 LMAT: 0x00000800 TYPE: KA1
MCAT: 0xeeccbe01 PCAT: 0xcda2b409 LMAT: 0x00100000 TYPE: KA1
MCAT: 0xf30cbe91 PCAT: 0xafaddd09 LMAT: 0x00040000 TYPE: KA0
MCAT: 0xeeecbe01 PCAT: 0xcda2b409 LMAT: 0x00100000 TYPE: KA0
MCAT: 0xcc000331 PCAT: 0x000fb109 LMAT: 0x00000800 TYPE: KA1
MCAT: 0xe554be01 PCAT: 0xcda2b409 LMAT: 0x00100000 TYPE: KA1
MCAT: 0xf30cbe91 PCAT: 0xafaddd09 LMAT: 0x00040000 TYPE: KA1

[download]

Prints:

MCAT: 0xf30cbe01 PCAT: 0xcda2b409 LMAT: 0x00100000 TYPE: KA0
MCAT: 0xcc3fbed1 PCAT: 0x000fb109 LMAT: 0x00000800 TYPE: KA1
MCAT: 0xeeccbe01 PCAT: 0xcda2b409 LMAT: 0x00100000 TYPE: KA1
MCAT: 0xf30cbe91 PCAT: 0xafaddd09 LMAT: 0x00040000 TYPE: KA0, KA1
MCAT: 0xeeecbe01 PCAT: 0xcda2b409 LMAT: 0x00100000 TYPE: KA0
MCAT: 0xcc000331 PCAT: 0x000fb109 LMAT: 0x00000800 TYPE: KA1
MCAT: 0xe554be01 PCAT: 0xcda2b409 LMAT: 0x00100000 TYPE: KA1

[download]
DWIM is Perl's answer to Gödel

In reply to Re^5: Checking LInes in Text File by GrandFather
in thread Checking LInes in Text File by Anonymous Monk

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