POSIX/nohup

Definition:

The command to ignore the HUP (hangup) signal.

It prevents the process from exiting when the terminal or ssh session is closed.

How to use it

Start a process

• In the terminal:
  • cd to the directory you'd like to start the process in.
  • Run:

nohup [commandYoudLikeToKeepRunningAfterClosed] > /dev/null 2>&1 & echo $! > process.pid

• This will start the process, and save a "process.pid" (process id number) file to the directory

• This is so that your filesystem has a record of which process is running, for use later.

Stop a process

• In the terminal:
  • cd to the directory that the applicable process was started in.
  • Run:

kill -9 `cat ./process.pid`

• This will read the "process.pid" file, and use the value previously saved to kill that process.