xargs.py

""" Construct argument list(s) and execute utility
"""

import os
import sys
import argparse

_stash = globals()['_stash']

def main(args):
    ap = argparse.ArgumentParser()
    ap.add_argument('-n',
                    nargs='?',
                    metavar='number',
                    type=int,
                    help='maximum number of arguments taken from standard input for each invocation of utility')

    ap.add_argument('-I',
                    dest='replstr',
                    nargs='?',
                    help='replacement string')

    ap.add_argument('utility',
                    nargs='?',
                    default='echo',
                    help='utility to invoke')

    ap.add_argument('args_to_pass',
                    metavar='arguments',
                    nargs=argparse.REMAINDER,
                    help='arguments to the utility')

    ns = ap.parse_args(args)

    lines = [line.strip() for line in sys.stdin.readlines()]
    n = ns.n if ns.n else len(lines)
    if ns.replstr:
        n = 1

    while lines:
        rest = ' '.join(lines[:n])
        lines = lines[n:]
        args_to_pass = ' '.join(ns.args_to_pass)

        if rest.strip():

            if ns.replstr:
                args_to_pass = args_to_pass.replace(ns.replstr, rest)
                rest = ''

            cmdline = '%s %s %s' % (ns.utility,
                                    args_to_pass,
                                    rest)

            _stash(cmdline)


if __name__ == "__main__":
    main(sys.argv[1:])