This may or may not be your issue, but it has certainly happened to me many times... But maybe Perl is right and you are wrong. Perhaps the file does not really contain lines with "fubar". Even if it looks like "fubar" is there, are you sure that there aren't control characters hidden in the file? e.g. ("fu^Abar")? It might be worthwhile to check.

And since I'm assuming that you aren't really looking for the literal text "fubar", there are other possible issues. Are you matching whitespace characters correctly? Is this a multi-line pattern? Maybe you should give us an exact example.

Update: 200th post!

buckaduck