lookup.py

#!/usr/bin/env python

import re
import optparse


def Main():
    parser = optparse.OptionParser("usage %prog -w <word> -f <file>")
    parser.add_option('-w', dest='word', type='string', help='specify a word to search for')
    parser.add_option('-f', dest='fname', type='string', help='specify a file to search')
    (options, args) = parser.parse_args()
    if (options.word == None) | (options.fname == None):
        print parser.usage
        exit(0)
    else:
        word = options.word
        fname = options.fname

    searchFile = open(fname)
    lineNum = 0

    for line in searchFile.readlines():
        line = line.strip('\n\r')
        lineNum += 1
        searchResult = re.search(word, line, re.M|re.I)

        if searchResult:
            print str(lineNum) + ': ' + line

if __name__ == '__main__':
    Main()