Starting the task in the background (add the & to the end of a command):
task-name &
Moving the task to the background:
press the CTRL-Z combination
Restoring the task from the background:
fg
Ending the task:
press the CTRL-C combination
Example of use:
tar cvzf backup.tgz /home & # start the task in the background
... # run any other commands you want
fg # restore the task from the background
# now you can check status of the command
# press ctrl+z to move it back to the background
... # run any other commands you want
fg # restore the task from the background again
# press ctrl-c to terminate the task