Prime check

gistfile1.py

from math import sqrt

def is_prime(n):
    if n is 2 or n is 3 or n is 5:
        return True

    if n % 2 == 0 or n % 3 == 0:
        return False

    sq = sqrt(n)
    i = 6
    while i < sq:
        if n % (i - 1) == 0 or n % (i + 1) == 0:
            return False
        i += 6

    return True

if __name__ == '__main__':
    import sys

    numbers = sys.argv[1:]
    if not numbers:
        print "Usage: {0} num [num1] ...".format(sys.argv[0])
        sys.exit(0)

    for n in numbers:
        print "{0} {1}".format(n, is_prime(int(n)))