in reply to
Edit huge file
First thing that pops into mind for me if you really want to avoid reading/re-writing entire file:
Read in file until you find line near start you want to delete (note line number using $.
Read in file in reverse until you find line near end to delete (can use File::ReadBackwards)
Use Tie::File to represent file as an array
Use splice to get rid of unwanted lines
Then untie @array;
Disclaimer: I have limited experience with Tie::File, so not sure how it performs w/ larger files.