Source

pythonwise / pfilter

#!/usr/bin/env python
'''Path filter, to be used in pipes to filter out paths.

* Unix test commands (such as -f can be specified as well)
* {} replaces file name

Examples:
    # List only files in current directory
    ls -a | pfilter -f

    # Find files not versioned in svn 
    # (why, oh why, does svn *always* return 0?)
    find . | pfilter 'test -n "`svn info {} 2>&1 | grep Not`"'
'''

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

from os import system

def pfilter(path, command):
    '''Filter path according to command'''

    if "{}" in command:
        command = command.replace("{}", path)
    else:
        command = "%s %s" % (command, path)

    if command.startswith("-"):
        command = "test %s" %  command

    # FIXME: win32 support
    command += " 2>&1 > /dev/null"

    return system(command) == 0

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

    from sys import stdin
    from itertools import imap, ifilter
    from string import strip
    from functools import partial

    if len(argv) != 2:
        from os.path import basename
        from sys import stderr
        print >> stderr, "usage: %s COMMAND" % basename(argv[0])
        print >> stderr
        print >> stderr, __doc__
        raise SystemExit(1)

    command = argv[1]
    # Don't you love functional programming?
    for path in ifilter(partial(pfilter, command=command), imap(strip, stdin)):
        print path

if __name__ == "__main__":
    main()