if ( $line =~ /([N01]{39})/ ) #### if ( $line =~ /([N01]{39});/ ) #### use strict; use warnings; while (my $line = ) { if ($line =~ /([N01]{39})$/) { print "line $.: <$1>\n"; } } __DATA__ #### Roboticus@Waubli ~ $ perl pm1208422.pl Roboticus@Waubli ~ $ #### Roboticus@Waubli ~ $ perl pm1208422.pl line 194: line 196: line 199: line 201: line 204: line 206: line 209: line 211: line 214: line 216: . . . et cetera . . .