Alex Ruben
How To Execute Programs in the Background Using the Ubuntu Terminal
Getting your head around background processes on Ubuntu can be a little confusing at first. Maybe you’ve run a long command, but don’t want to wait around for it to finish, or you need to kick off multiple things at once without losing control of the terminal. It’s one of those fundamental Linux skills that kinda feels like magic the first time you pull it off. The goal here? Show how to start programs in the background, check on them, and even keep them running after you close the terminal—because, of course, Ubuntu has to make it harder than it needs to be.
Once you get the hang of these tricks, your workflow gets a lot smoother, especially if you’re running the same tasks repeatedly or want to keep things ticking in the background without manual intervention. Expect to see commands like &, jobs, fg, and nohup show up here, along with some real-world tips based on what’s actually worked for folks in the trenches.
How to Run and Manage Background Processes in Ubuntu
Run a Command in the Background
Starting with the basics: if you want to run a command, like milkingsleep or whatever, in the background, just slap an & at the end. Here’s why that works: the & tells the shell, “Hey, don’t wait for this to finish—run it and move on.”
For example, you’re doing something like:
sleep 120 &That will kick off a sleep command for 2 minutes but free up your terminal instantly. On various setups, it might flash a job number and process ID, indicating it’s alive and running in the background. The thing is, on some machines, this sometimes fails the first time if the terminal session is overreactive or if you’re running scripts or remote sessions. If it doesn’t seem to work initially, try typing it again or check if your shell is configured to handle job control properly.
View All Running Background Jobs
Use jobs to see what’s floating around in the background. It lists all active jobs you started from that terminal. Sometimes, it’s hard to remember which process was which, especially if you’ve got several running. This is handy to keep track of stuff without resorting to ps commands or other more complicated tools.
jobsIf it’s not showing up, maybe you forgot to start it with &, or the session has lost track. Also, jobs might be stopped or in a weird state, so check with ps aux | grep [your_process] if needed.
Bring a Background Process Back to the Foreground
Sometimes you wanna actually interact with the process again. fg is the magic command that pulls a job back into the “running” state. You can specify the job number if you’ve got more than one — like fg %1.
Make sure you know what job number to use: it’s shown next to the process when you run jobs. This is super useful if you need to see output or stop the process early. In practice, on some setups, bringing things to the foreground can be flaky if the shell isn’t tracking jobs right. Keep that in mind.
Keep Processes Running After You Close the Terminal
This is sometimes the most critical part. You might want to start a long process, like a backup or a download, and then shut the terminal or disconnect from SSH without killing it. The tool for that is nohup. It effectively says, “Don’t hang up”—letting your process run even if your SSH session drops or you close the terminal window.
Example command:
nohup sleep 3600 & This will keep the sleep running for an hour, even if you log out. Usually, nohup redirects output to a file named nohup.out by default, but you can customize that if needed. Be aware, though—sometimes, if you’re not redirecting output explicitly, you might end up with a lot of logs in the current directory. Also, some shell configs may interfere, so double-check if it’s not working as planned.
Dealing with Output and Clutter
When running commands in the background, output can pile up and clutter your terminal or log files. You can redirect both stdout and stderr to a file, which is usually smarter, especially for long-running processes. For example:
my_command > output.log 2>&1 &This sends all output and errors into output.log. Not all commands play nicely with background operation, so keep an eye on output files and logs to spot any issues early. Also, if you forget the &, your shell will hang, thinking you’re still in the foreground, which is kind of frustrating.
Extra Tips & Common Pitfalls
One weird thing is sometimes the job control doesn’t seem to behave consistently across different Linux setups or shells. On some machines, background jobs might terminate unexpectedly if the terminal gets closed unless you used nohup. Also, if the process outputs to your terminal directly, it can mess up your prompt or obscure other data. Redirecting output is almost always recommended.
Conclusion
Managing background processes in Ubuntu isn’t rocket science, but it’s a little quirky and sometimes unintuitive. The main takeaway? Use & to start tasks in the background, check on them with jobs, bring them back with fg, and keep them alive after closing the terminal with nohup. A few tweaks here and there can really make multitasking smoother, especially on remote servers or heavy-duty tasks.
Frequently Asked Questions
Why would I run processes in the background?
Basically, so you’re not stuck waiting around. You can launch a long task and keep working on other stuff or close the terminal if you used nohup without worrying about it stopping.
Can I see background jobs after I’ve closed the terminal?
Usually not, unless you used nohup or a terminal multiplexer like tmux or screen. Otherwise, all jobs die with the session.
What’s the magic to kill a background process?
You find its process ID with ps or kill it directly with kill. Be careful—kill with -9 should be a last resort because it forcefully terminates the process.