_data.txt_
abc:AB CD:100
def:DE FG:101
ghi:GH IJ:102
abc:AB CD:100
ghi:GH IJ:103

##</code><code>##

my $file='source_data\data.txt';
open FILE, $file or die "FILE $file NOT FOUND - $!\n";

while (<FILE>){
        chop $_;
        my ($a, $b, $c) = split /:/, $_;
        my $r = [$a, $b, $c];
        my @arr = $r->[0];
       
        my @matches = grep $_ eq "abc", $arr[0];
        
        foreach my $i (@matches) {
        print $_."\n";
        }
}


##</code><code>##

_ouput_
abc:AB CD:100
abc:AB CD:100