How to keep a process open when closing the SSH session?

Clarifications:

1. tmuxand screenthey're not primarily for what you want, they're a multiplexer and a terminal emulator respectively. Allowing you to keep a process running on a remote server is not its main feature. To use them only for that is to underutilize them and leave too many programs running on your remote server.

2. Contrary to what @patapalo said, the '&' character does not keep a process open after logging out. What it does is it passes it to the background allowing the shell it was run from to continue working. If you close the ssh connection this process stops.

What you need is the program nohupthat is designed for that.

The way to run nohup is as follows:

nohup ./programa &

What it does makes nohupa program ignore the SIGHUP signal. When you run a program and then exit the terminal, even though you ran it in the background with ./programa &, the program receives a SIGHUP signal which suspends execution of the program. Instead, with nohupyou can continue running the program despite closing the ssh session or sending a signal like kill -1 pid_del_programa.

To kill it, you just have to kill the process associated with the program, either with kill (of course, as long as you don't send the 1 or SIGHUP) signal, or with some process viewer, etc.

You can run the process using screen:

SCREEN comando Argumentos

and then you do a detach of screenpressing Ctrl+ Aand then Ctrl+ D.

You can then close the SSH session.

I would recommend you to use tmux( terminal multiple x er ), it is more modern and has some advantages over screen.

Advantage

According to the FAQ :

• Use a client-server model
• Different command interfaces
• can be extended
• It is possible to limit the size of the window
• Has search support
• The model for the division of windows (split) is different. tmuxit has two objects, window and panel; screenit only has windows.

Use

Note that you must run tmuxon the server you connect to via SSH, in the examples I'm assuming you've already connected.

By default, it tmuxuses the Ctrl+ combination bas a shortcut to execute the commands, but for the examples I will use the commands without shortcuts.

It is preferable to name your sessions to maintain order, with the following simple example you can create a new session:

$ tmux new -s prueba

Well, now you have a session that you could return to even after logging out and find everything just the way you left it, let's test this by running a simple command:

$ pwd
/home/cesar

To exit the session (detach):

$ tmux detach

And you should be back to the beginning where you created the session:

$ tmux new -s prueba
[detached]
$

You can see the active sessions:

$ tmux ls
prueba: 1 windows (created Mon Feb 15 08:32:51 2016) [151x36]

To re-enter the session (attach):

$ tmux attach -t prueba

And now you should find things as you left them last time (including the command tmux detach):

$ pwd
/home/cesar
$ tmux detach
$ 

If you want to end the session (kill):

$ tmux kill-session -t prueba

There should no longer be sessions:

$ tmux ls
failed to connect to server

Well, these are some basic commands that show the benefits of tmux, although as I mentioned above it is even faster to use the commands using shortcuts with Control+ b.

References

• Official site
• Manual
• GitHub repository

I get a command to continue executing by adding an & to the end.

I think it's like telling it to run in the background and not run in the ssh shell

For example java -jar xxx.jar &