How to prevent a background process from being stopped after closing SSH client in Linux

Question

I\'m working on a Linux machine through SSH (Putty). I need to leave a process running during the night, so I thought I could do that by starting the process in background (

Answer 1

For most processes you can pseudo-daemonize using this old Linux command-line trick:

# ((mycommand &)&)

For example:

# ((sleep 30 &)&)
# exit

Then start a new terminal window and:

# ps aux | grep sleep

Will show that sleep 30 is still running.

What you have done is started the process as a child of a child, and when you exit, the nohup command that would normally trigger the process to exit doesn't cascade down to the grand-child, leaving it as an orphan process, still running.

I prefer this "set it and forget it" approach, no need to deal with nohup, screen, tmux, I/o redirection, or any of that stuff.