import sys

def main(args):
    if args == ['error']:
        print >> sys.stderr, "stderr output"
        return
    if args[:1] == ['exit']:
        sys.exit(int(args[1]))
    if args == ['stdin']:
        print sys.stdin.read().upper()
        return
    for arg in args:
        print 'Writing %s' % arg
        open(arg, 'w').write('test')

if __name__ == '__main__':
    main(sys.argv[1:])