bash 注销时bash如何处理作业？

How bash handles the jobs when logout?

提问by Unni

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 :

据我从书籍和 bash 手册中了解到的是。当用户从 bash 注销时，如果用户未使用 nohup 或 disown，则该用户启动的所有后台作业将自动终止。但是今天我测试了它：

1. Logged in to my gnome desktop and accessed gnome-terminal.

2. There are two tabs in the terminal and in one I created a new user called test and logged in as test

   su - test
   

3. started a script.

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

4. After that I logged out of test and closed the tab

5. In the next tab I exected ps aux as root and found that job is still running.

1. 登录到我的 gnome 桌面并访问 gnome-terminal。

2. 终端中有两个选项卡，其中一个我创建了一个名为 test 的新用户并以 test 身份登录

   su - test
   

3. 启动了一个脚本。

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

4. 之后我退出了测试并关闭了选项卡

5. 在下一个选项卡中，我以 root 身份执行 ps aux 并发现该作业仍在运行。

How this is happening ?

这是怎么回事？

回答by jilles

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.

正在运行的后台作业是否在退出时终止取决于 shell。Bash 通常不会这样做，但可以配置为用于登录 shell ( shopt -s huponexit)。在任何情况下，在控制进程（例如登录 shell）终止后，都无法访问 tty。

Situations that do always cause SIGHUPinclude:

确实会导致的情况SIGHUP包括：

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

• tty 关闭时前景中的任何内容。
• 任何包含在 shell 终止时停止的进程的后台作业（SIGCONT和SIGHUP）。壳牌通常会在发生这种情况之前警告您。

huponexit summary:

huponexit总结：

• 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
  

• On：当 shell 退出时，后台作业将用 SIGHUP 终止

  $ shopt -s huponexit
  $ shopt huponexit
  huponexit       on
  

• Off：当 shell 退出时，后台作业不会用 SIGHUP 终止。

  $ shopt -u huponexit
  $ shopt huponexit
  huponexit       off
  

回答by thejh

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.

只有交互式 shell 在您关闭作业时才会终止作业。其他外壳（例如您通过使用 获得的外壳su - username）不会这样做。交互式 shell 只会杀死直接的子进程。