如何始终在 linux (ubuntu) 中运行 python 脚本

Question

I have a linux system server using ssh to connect. Now I have a python script.I want it run always.I using this commond

ubuntu:~$ nohup python3 -u ~/test/main.py > test.outs 2>&1 &

but I exit ssh connect,That python script exit at the same time. What should I do?

Answer 1

You could run the script regularly / check it is running with a cronjob and this would also allow you to run the script at system start-up so it would keep running in the event of a reboot.

There are a few suggestions here; https://superuser.com/questions/448445/run-bash-script-in-background-and-exit-terminal

Although this also suggests that nohub should stop the child process being killed when you exit the session. How are you aware that the script stops running upon exit?

Answer 2

There are multiple ways to do this and they depend on your use-case.

One way to do it is to install 'screen' on your server.

sudo apt-get install screen

Now, whenever you connect to your server with ssh, you can type 'screen' and then start your code there. (first time you do this, you get an explanation on screen, press space to skip it)

With this code executing, you type Ctrl + A and then Ctrl + D. This 'detaches' the screen. You can now disconnect and this 'screen' will keep existing and the code will still run.

When reconnecting, you might want to go back to this screen. Type

screen -ls

to get an overview of screens that you have running. (in this case, there'll only be one) They can be identified by the 5 numbers they all start with. So go back to this screen by typing

screen -r XXXXX

and now you're back. More information on this here:

https://www.howtogeek.com/662422/how-to-use-linuxs-screen-command/

Again, I don't know what your script does so it might not be the best solution.

Answer 3

You may use screen

After installation, you can start screen by sending screen to the console, and then run your script. When you type CTRL+A+D , the screen will disappear and you can exit your ssh connection.

If you re-open the screen you opened before, just type screen -r

If you have multiple screen instances, the app will show you numbers of screen when you type screen -r . You just need to find the id of the screen and type screen -r id ie screen -r 2643