* Charlie Reiman (creiman@kefta.com) [021204 18:26]: > > -----Original Message----- > > From: Rob VanFleet [mailto:rvf@linux.wku.edu] > > Sent: Wednesday, December 04, 2002 5:40 PM > > > > I am writing a script that will compress certain files passed to it > > (well, that's a part of the script) and I was wondering if there was a > > simple way to determine if a file is worth compressing or not. I know > > that with some very small files, compression actually increases the file > > size. Should I just look at the file size and only compress if over a > > certain size or is there a more efficient method? > Not really. The best (indeed, only 100% accurate) way to determine if a file > is compressible is to compress it. That doesn't mean you can't use some good > heuristics. Good ones are: > > filename suffixes (never bother with gz, tgz, bz2, zip, jpg, jpeg, gif, z, > Z, mpg, mpeg, avi, wav, mov....) Huh? some AVIs and all WAVs are uncompressed, and will benefit enormously from compression. The theory here is correct, though: don't try to compress already-compressed data; it won't work. > compress a sample of the file (first and last 4k blocks maybe?) > test for magic numbers that indicate compressed types > Don't bother for files less than 1k Or tar them up and compress the whole thing. If you have a lot of little text files, or a lot of little wavs, you'll save a lot of space with a compressed tarball. good times, Vineet -- http://www.doorstop.net/ -- --Nick Moffitt A: No. Q: Should I include quotations after my reply?
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