How bash handles the jobs when logout?

问题

As far as I understood from the books and bash manuals is that. When a user logs out from bash all the background jobs that is started by the user will automatically terminate, if he is not using nohup or disown. But today I tested it :

Logged in to my gnome desktop and accessed gnome-terminal.
There are two tabs in the terminal and in one I created a new user called test and logged in as test
```
su - test
```

started a script.

cat test.sh
#!/bin/bash
sleep 60
printf "hello world!!"
exit 0


./test.sh &

After that I logged out of test and closed the tab
In the next tab I exected ps aux as root and found that job is still running.

How this is happening ?

回答1:

Whether running background jobs are terminated on exit depends on the shell. Bash normally does not do this, but can be configured to for login shells (shopt -s huponexit). In any case, access to the tty is impossible after the controlling process (such as a login shell) has terminated.

Situations that do always cause SIGHUP include:

Anything in foreground when the tty is closed down.
Any background job that includes stopped processes when their shell terminates (SIGCONT and SIGHUP). Shells typically warn you before letting this happen.

huponexit summary:

On: Background jobs will be terminated with SIGHUP when shell exits
```
$ shopt -s huponexit
$ shopt huponexit
huponexit       on
```
Off: Background jobs will NOT be terminated with SIGHUP when shell exits.
```
$ shopt -u huponexit
$ shopt huponexit
huponexit       off
```

回答2:

Only interactive shells kill jobs when you close them. Other shells (for example those you get by using su - username) don't do that. And interactive shells only kill direct subprocesses.

来源：https://stackoverflow.com/questions/4298741/how-bash-handles-the-jobs-when-logout

标签

Linux

bash

nohup