unpack

I always have trouble remembering which command opens which archive (.tar.gz, .bz2, .zip ...). This is why I have a handy little utility the called "unpack" that knows by the file extension which command to call:

#!/usr/bin/env python
'''Unpack/show compressed files

Create a symbolic link called "zview" to this file or specify -l to view
'''

__author__ = "Miki Tebeka <miki.tebeka@gmail.com>"

from os import system
from os.path import splitext, isfile
from operator import itemgetter

def _stdout(cmd, filename):
    return "%s '%s' > '%s'" % (cmd, filename, splitext(filename)[0])

def bz(filename):
    return _stdout("bzip2 -d -c", filename)

def gz(filename):
    return _stdout("gunzip -c", filename)

class Archive:
    extensions = {} # Extension -> instance

    def __init__(self, unpack, list, extensions):
        self.unpack = unpack
        self.list = list
        for ext in extensions:
            Archive.extensions[ext] = self

Archive("tar -xzvf", "tar -tzf", [".tar.gz", ".tgz", ".tar.z"]),
Archive("tar -xjvf", "tar -tjf", [".tar.bz", ".tar.bz2"]),
Archive(bz, "", [".bz", ".bz2"]),
Archive("tar -xvf", "tar -tf", [".tar"]),
Archive("unzip", "unzip -l", [".zip", "jar", "egg"]),
Archive("unarj e", "unarj l", [".arj"]),
Archive(gz, "", [".gz", ".Z"]),
Archive("unrar x", "unrar lb", [".rar"]),
Archive("7za x", "7za l", [".7z"])

def find_archive(filename):
    # Find *longest* matching extension
    for ext in sorted(Archive.extensions, reverse=1, key=len):
        if filename.lower().endswith(ext):
            return Archive.extensions[ext]

def main(argv=None):
    if argv is None:
        import sys
        argv = sys.argv

    from optparse import OptionParser
    parser = OptionParser(usage="usage: %prog [options] FILE")
    parser.add_option("-s", "--show", help="just show command, don't run",
        dest="show", action="store_true", default=0)
    parser.add_option("-l", "--list", help="list files in archive", 
        dest="list", action="store_true", default=0)


    opts, args = parser.parse_args(argv[1:])
    if len(args) != 1:
        parser.error("wrong number of arguments") # Will exit

    infile = args[0]
    if (not opts.show) and (not isfile(infile)):
        raise SystemExit("error: can't find %s" % infile)

    archive = find_archive(infile)
    if not archive:
        raise SystemExit("error: don't know how to handle %s" % infile)
    list = opts.list or ("zview" in __file__)
    command = archive.list if list else archive.unpack

    infile =  infile.replace("'", "\\'")

    if callable(command):
        command = command(infile)
    else:
        command = "%s '%s'" % (command, infile)

    if opts.show:
        print command
        raise SystemExit

    raise SystemExit(system(command))

if __name__ == "__main__":
    main()

There is also a similar one for viewing zip content.