git-clone-both

#!/usr/bin/env python

def classify_args(args):
    flags = []
    others = []
    for i, arg in enumerate(args):
        if arg == "--":
            others.extend(args[i + 1:])
            break
        elif arg.startswith("-"):
            flags.append(arg)
        else:
            others.append(arg)
    return flags, others

def guess_dir_name(repo):
    import re
    '''partly based on guess_dir_name in git/builtin/clone.c;
    we try to be more strict however'''
    m = re.search(r"([A-Za-z0-9._-]+)[/\\]?(\.git)?$", repo)
    if not m:
        return
    return m.group(1)

def main(arg0, *args):
    import os, subprocess, sys
    prog = os.path.basename(arg0)

    flags, others = classify_args(args)

    try:
        origin = others[0]
        source = others[1]
    except IndexError:
        sys.stderr.write(USAGE.format(prog))
        exit(1)

    try:
        dest = others[2]
    except IndexError:
        dest = guess_dir_name(origin)
        if not dest:
            sys.stderr.write("""
    {0}: unable to guess destination directory
    {0}: please specify DEST explicitly
    """[1:].format(prog))
            exit(1)

    subprocess.check_call(["git", "clone"] + flags +
                          ["--", others[0]] + others[2:])
    os.chdir(dest)
    subprocess.check_call(["git", "remote", "add", "source", source])
    subprocess.check_call(["git", "fetch", "--all"])

USAGE = "usage: {0} ORIGIN SOURCE [DEST] [FLAGS...]\n"

if __name__ == "__main__":
    import subprocess, sys
    try:
        main(*sys.argv)
    except KeyboardInterrupt:
        exit(2)
    except subprocess.CalledProcessError as e:
        exit(e.returncode)