http://www.perlmonks.org?node_id=1057458


in reply to Comparing strings from different files

that is ugly but working
while( <> ){ while(/(E99|99)(\w+)(?=\|)|\n/){ $key .= $`; $hash{$key}++; $key = '->'.$2; $_ = $'; } } foreach (sort keys %hash){ print "$_ $hash{$_}\n" if $hash{$_} >= 2; }
run it like ./script.pl FILE1 FILE2
output will be yours repeating lines,
accordingly == 1 will show you unique lines
P.S. and turn out warnings)
P.P.S. sorry for ugliness