Searching through large textfile

[Das_boot]

I was wondering if anyone could tell me what is the fastest way to search through a large (~100 000 lines) textfile? For now my code is this:

1. Get user searchword(s)
2. Take 1st line of text from file and make it array
3. Compare (in_array) array to searchword(s) and output if found in array
4. Take 2nd line and so on...

This is very slow procedure. If anyone could point out a faster way to do things, it would be appreciated.

[bpat1434]

you could always do a strpos() of the search words.....