import sys
import os
a = []
def main():
    print "Listkeeper v.0.01."
    print ("Files here: ")
    sorted_dir = sorted(os.listdir("."))
    for file in len(sorted_dir):
        files.append(file)
    for number in len(a):
        print (("[{0}]    {1}/n").format((number),(a[number]))
    print ("End")
main()

 File "list.py", line 12
    print ("End")
        ^
SyntaxError: invalid syntax

 print "Listkeeper v.0.01."

 print ("Files here: ")

 print (("[{0}]    {1}/n").format((number),(a[number]))

 for file in len(sorted_dir):

 import sys
import os
def main():
    print ("Listkeeper v.0.01.\n","Files here: ")
    for number,file in enumerate(sorted(os.listdir())):
        print ('{} {}'.format(number+1,file))
    print ("End")
main()