hum, I don't see how this snippet can possibly print what you say it does, or anything at all, for that matter.

For starters, E0+ is much shorter than 34 chars long, so the only print that isn't commented won't get executed because the if will fail (unless $_ is 32 chars long and ends with 'E0+').

And then, there's the issue that you are printing $1, yet the last regexp you execute (m/st_9840_acs_0/) doesn't have any captures.

btw, I think you're using java-style substring arguments. perl uses substr(string, start, length), not substr(string, start, end)