如何从 python 运行多个外部命令？

Question

I know there are available options like os and subprocess but they don't just do what I want yet Let's say I have a list of external commands. myList = ['cd desktop','mkdir spotify'] and I want to run them all at once from python, I don't want to use os.chdir or any sub process method because that list is based up of user input and I can't just know in what index of the list they have to cd into a project, please help

Answer 1

So, the basic worry comes is about the cd command. for which we can make exceptional case by simply spliting and checking if the command is cd which will detect weather the command is cd or not.

So we will start of by making a function that will check our command

import os
import shlex

def is_cd(command: str) -> bool:
    command_split = shlex.split(command)
    return command_split[0] == "cd"  # this returns True if command is cd or False if not

now we can use our above function to identify if the command is cd or not. Then we need to execute the command for which we will use the function below

def run_command(command: str) -> int:
    if is_cd(command):
         split_command = shlex.split(command)
         directory_to_change = ' '.join(split_command[1:])
         os.chdir(directory_to_change)
    else:  # if its a regular command
        os.system(command)

so our final code becomes

import os
import shlex

def is_cd(command: str) -> bool:
    command_split = shlex.split(command)
    return command_split[0] == "cd"  # this returns True if command is cd or False if not


def run_command(command: str) -> int:
    if is_cd(command):
         split_command = shlex.split(command)
         directory_to_change = ' '.join(split_command[1:])
         os.chdir(directory_to_change)
    else:  # if its a regular command
        return_code = os.system(command)
        if return_code != 0:  # If command failed to run then
            pass  # you can do something here


if __name__ == "__main__":
    user_commands = ["mkdir testdir", "cd testdir"]
    for command in user_commands:
        run_command(command)

Here are some extra links to understand the concepts:

• shlex
• os