First, thanks!

And: There is no "end-section". the end is the start of the next section and a "start-section" is one of 5-6 different tags that implemebt some kind of hierarchy between sections.
I still can parse the big file into files but in any case I need to save a data struct with the files names, sections headers, etc. so it seems as a double wrok.

I finally solved it by Tie::File module, reading "line by line" from the tie array, and save for each section its name, its place at hierarchy and start and end index.
I ended up with one read of the whole file, and then direct access to each section by its name.

However, I was worried about the size of the tie array, but I guess it won't be bigger than 4 or 8 bytes multiple by the number of lines. I can live with (and correct me if I'm wrong :-)).

thanks again!
Keren.