Generates unique filenames.

unique.py

# Generates a new unique filename if the provided filename already exists,
# otherwise just return the provided filename.
# Usage: python unique.py name/of/file
import os
import sys


def increment(filename):
    last = filename.split()[-1]

    try:
        # If the filename ends in a number increment that number
        num = int(last)
        new = filename.rstrip(last) + str(num + 1)
    except ValueError:
        # If the filename doesn't end in a number append one
        new = ' '.join([filename, '1'])

    return new


def unique(filename):
    while os.path.exists(filename):
        filename = increment(filename)

    return filename


def main():
    print(unique(sys.argv[1]))


if __name__ == '__main__':
    main()