lines.py

#!/usr/bin/env python

# Author : Sankalp Khare
# Date   : [2014-07-22 Tue]


# the filenames and the query word are hardcoded right now, can be parameterized later as command line arguments
file1="a.txt"
file2="b.txt"
query="this"

def main():
    '''read the lines of one file, pick out those that contain a word specified by the user on the commandline, and then output those lines of the second file with the same line numbers'''

    with open(file1) as f1, open(file2) as f2:
        for linein1,linein2 in zip(f1.readlines(),f2.readlines()):
            if query in linein1:
                print linein2

if __name__ == '__main__':
    main()