Question

So I’m writing a shell in Python, and the filename is jsh.py. When I run the code, it doesn’t work for some reason. A window pops up but closes immediately. What is worng with my code?

import os
import random
import time
import path
import string
import sys

commandAvail = 'ls where chdir mk mkdir cp mv rm rmdir view ext shutdown edit unix dos man-all man-unix man-dos'
commandAvailUnix = 'exec permission group'
commandAvailDos = ' '
print('Welcome to jsh alpha 1!')
commandPlatform = input('System: (UNIX/DOS):')
commandLine()

def commandLine():
        while 1 == 1:
                command = input('$ ')
                if command in commandAvail:
                        if command.startswith('ls'):
                                commandKeyword = 'ls'
                                commandOptions = command - commandKeyword
                                ls(commandOptions)
                        elif command.startswith('where'):
                                commandKeyword = 'where'
                                commandOptions = command - commandKeyword
                                where()
                        elif command.startswith('chdir'):
                                commandKeyword = 'chdir'
                                commandOptions = command - commandKeyword
                                chdir()
                        elif command.startswith('mk'):
                                commandKeyword = 'mk'
                                commandOptions = command - commandKeyword
                                mk()
                        elif command.startswith('mkdir'):
                                commandKeyword = 'mkdir'
                                commandOptions = command - commandKeyword
                                mkdir()
                        elif command.startswith('cp'):
                                commandKeyword = 'cp'
                                commandOptions = command - commandKeyword
                                cp()
                        elif command.startswith('mv'):
                                commandKeyword = 'mv'
                                commandOptions = command - commandKeyword
                                mv()
                        elif command.startswith('rm'):
                                commandKeyword = 'rm'
                                commandOptions = command - commandKeyword
                                rm()
                        elif command.startswith('rmdir'):
                                commandKeyword = 'rmdir'
                                commandOptions = command - commandKeyword
                                rm()
                        elif command.startswith('view'):
                                commandKeyword = 'view'
                                commandOptions = command - commandKeyword
                                rm()
                        elif command.startswith('edit'):
                                commandKeyword = 'edit'
                                commandOptions = command - commandKeyword
                                edit()
                        elif command == 'man-all':
                                print('Commands that work for all underlying platforms:')
                                print(commandAvail)
                        elif command == 'man-unix':
                                print('Commands that only work on Unix systems:')
                                print(commandAvailUnix)
                        elif command == 'man-dos'
                                print('Commands that only work on DOS systems:')
                                print(commandAvailDos)
                        elif command.startswith('unix'):
                                commandType = 'unix'
                                unix()
                        elif command.startswith('dos'):
                                commandType = 'dos'
                                dos()
                        elif command.startswith('ext'):
                                commandKeyword = 'ext'
                                commandOptions = command - commandKeyword
                                ext()
                        elif command == 'shutdown':
                                sys.quit(0)
                        else:
                                print('jsh has experienced an internal error and has to shutdown.')
                                sys.quit(10)
                else:
                        print('Command \'' + command + '\' not recognized as internal or external.')

def ls(options):
        if commandPlatform == 'UNIX':
                os.system('ls' + options)
        else:
                os.system('dir' + options)
        commandLine()

Answer 1

You forgot to put ‘:’ after elif command == ‘man-dos’

Just run: python3 yourscript for debugging purposes.