Background Tasks

To see a list of your background processes, run ps -u <NetID>. You can kill a task with kill <PID>.

Nohup

If you just want to run a single command on the login node in a way that continues running even when logged out, you can use nohup. It is very simple. Simply run nohup <command> & and then hit enter. By default, any standard output will be written to nohup.out, and you can see the process with ps -u <NetID>.

tmux

For more involved background processes, especially in scenarios where you my want to interact with the process itself, tmux is the best choice. See the Research Computing  documentation  for details. An example is below:
tmux new -s mysession  # Start a new tmux session
command &              # Run a command in the background
>>> Ctrl + B, then D       # Detach from the session
tmux attach -t mysession  # Reattach later