Hitler Combos

import sys
import os
a = 0
filenames = {}
generationOptions = []
generatedLines = 0


def openfile(file):
    global filenames
    if os.path.isfile('./{0}.txt'.format(file)):
        filenames[file] = open("{0}.txt".format(file), "r+")
    else:
        os.mknod("{0}.txt".format(file))
        filenames[file] = open("{0}.txt".format(file), "r+")


def exitprogram(message):
    input(message)
    sys.exit()


combolist = open("combo.txt", "r")
print(
    "[0] Help (Read me first)\n[1] Remove short lines\n[2] Remove long lines\n[3] Remove duplicates\n[4] Count lines\n[5] Split user/pass\n[6] Transform mail:pass to user:pass\n[7] Create combo from usernames\n[8] Add string at the end of each line"
)
optionchoice = int(input("->"))
if optionchoice is 0:
    print(
        "This program should NOT be in the same folder as files bearing one of these names : user.txt , pass.txt , output.txt , as these could be overwritten and lost.\n"
    )
    print(
        "However, you NEED to put your combo in the same folder as this program, named combo.txt or usernames.txt depending on the option you want to use.\n"
    )
    print(
        "For the combo creator, use %user% and %USER% to use the username, without and with caps. If the username is John and you type %user%%USER%1, the generated line will be JohnJOHN1."
    )
if optionchoice is 1:
    openfile("output")
    minimum = int(input("Minimum number of characters ?"))
    removedlines = 0
    for line in combolist:
        if int(len(line)) > minimum:
            filenames["output"].write(line)
        else:
            removedlines += 1
    print("{0} removed lines, the new combolist is available in output.txt.".
          format(removedlines))
    filenames["output"].close()
    exitprogram("Done. Press enter to leave.")
elif optionchoice is 2:
    openfile("output")
    maximum = int(input("Maximum number of characters ?"))
    removedlines = 0
    for line in combolist:
        if int(len(line)) < maximum:
            filenames["output"].write(line)
        else:
            removedlines += 1
    print("{0} removed lines, the new combolist is available in output.txt.".
          format(removedlines))
    filenames["output"].close()
    exitprogram("Done. Press enter to leave.")
elif optionchoice is 3:
    openfile("output")
    duplicates_n = 0
    duplicates = set()
    for line in combolist:
        if line not in duplicates:
            filenames["output"].write(line)
            duplicates.add(line)
        else:
            duplicates_n += 1
    print(
        "{0} duplicate lines removed, the new combolist is available in output.txt.".
        format(duplicates_n))
    filenames["output"].close()
    exitprogram("Done. Press enter to leave.")
elif optionchoice is 4:
    lines = 0
    for line in combolist:
        lines += 1
    print("{0} lines in the combolist.".format(lines))
    exitprogram("Done. Press enter to leave.")
elif optionchoice is 5:
    openfile("user")
    openfile("pass")
    lines = 0
    for line in combolist:
        line = line.rstrip()
        username, password = line.split(":")
        filenames["user"].write(username, "\n")
        filenames["pass"].write(password, "\n")
    filenames["user"].close()
    filenames["pass"].close()
    exitprogram("Done. Press enter to leave.")
elif optionchoice is 6:
    openfile("output")
    for line in combolist:
        line = line.rstrip()
        username, password = line.split(":")
        user, mail = line.split("@")
        outputline = "{0}:{1}\n".format(user, password)
        filenames["output"].write(outputline)
    filenames["output"].close()
    exitprogram("Done. Press enter to leave.")
elif optionchoice is 7:
    while a is not 1:
        generateOption = input("Please input a format. To stop, type 0.\n")
        if generateOption is "0":
            a = 1
        else:
            generationOptions.append(generateOption)
    with open("user.txt", "r") as u:
        openfile("output")
        for line in u:
            line = line.rstrip()
            userName = line
            for i in range(len(generationOptions)):
                passWord = generationOptions[i]
                passWord = passWord.replace("%user%", userName)
                passWord = passWord.replace("%USER%", userName.upper())
                passWord = passWord.replace("%User%", userName.title())
                passWord = passWord.replace("%useR%", userName[0:len(userName)-1]+userName[len(userName)-1].upper())
                comboOutput = "{0}:{1}\n".format(userName, passWord)
                filenames["output"].write(comboOutput)
                generatedLines += 1
    filenames["output"].close()
    exitprogram("{0} generated lines. Press enter to leave.".format(generatedLines))
elif optionchoice is 8:
  openfile("output")
  ajoute = input("What string do we add ?")
  for line in combolist:
    filenames["output"].write(line.rstrip('\n') + ajoute + "\n")
else:
    exitprogram("Invalid command. Press enter to leave.")