#!/usr/bin/env python
#
# My own sane implementation of cut(1) - by default it
# parses columns on ANY whitespace instead of being picky.
#
# 2006 David A. Riggs <david.a.riggs@gmail.com>
#

import sys


'''parse a slice from a string'''
def parse_slice(st):
    # st can be 5, 5-, -5, 5-7
    if st.endswith('-'):
        sl = slice(int(st[:-1])-1, None)
    elif st.startswith('-'):
        sl = slice(None, int(st[1:]))
    elif st.count('-'):
        start, stop = st.split('-')
        sl = slice(int(start)-1, int(stop))
    else:
        sl = slice(int(st)-1, int(st))
    return sl


'''read from stream ins, write to outs'''
def pycut(delim, field, outdelim, ins, outs):
    s = parse_slice(field)
    for line in ins:
        toks = line.strip().split(delim)[s]
        print >> outs, outdelim.join(toks)


def main():
    from optparse import OptionParser

    desc = 'Print selected parts of lines from stdin to stdout. More sane than `cut`.'
    parser = OptionParser(version='%prog 0.1', description=desc)
    parser.add_option('-d', '--delim', dest='delim',
                      help='Use specified string instead of whitespace for delimiter')
    parser.add_option('-f', '--field', dest='field',
                      help='Output only these fields, eg. 3, 3-, -3, 3-5')
    parser.add_option('-o', '--output-delimiter', dest='outdelim',
                      help='Use OUTDELIM as output delimiter instead of space')
    parser.set_defaults(outdelim=' ')
    
    opts, args = parser.parse_args()

    pycut(opts.delim, opts.field, opts.outdelim, sys.stdin, sys.stdout)


if __name__ == '__main__':
    main()