Wraplines.py

Apply a pattern to all lines in a text file.

Usage: wraplines.py source destination pattern [encoding]
Example: wraplines data.txt - '%s',\n\n iso-8859-13

from codecs import open
from sys import argv

def main():
    if len(argv) < 4:
        exit('usage: %s source destination pattern [encoding]' % argv[0])
    sourcename, destname, pattern = argv[1:4]
    pattern = pattern.decode('string_escape')
    if destname == '-': destname = sourcename
    try: charset = argv[4]
    except IndexError: charset = 'utf-8'
    source = open(sourcename, 'U', charset).read().split('\n')
    dest = open(destname, 'w', charset)
    for lines in xrange(len(source)):
        dest.write(pattern % source.pop())
    dest.close()
    print '%d lines written to %s' % (lines * pattern.count('\n') + 1, destname)

if __name__ == '__main__':
    main()