Learn
What Is a Daemon on Linux
Background processes like sshd or cron, and how to manage them with systemctl.
A daemon is a program that runs in the background, with no visible interface, waiting to perform a specific task when needed.
Everyday examples
- sshd: waits for remote SSH connections.
- cupsd: manages print jobs.
- cron: runs scheduled tasks at defined times.
The name comes from a convention — many daemons end in "d" (sshd, cupsd, systemd) precisely to indicate they're this type of process, running without anyone directly watching them.
Viewing and managing daemons
systemctl list-units --type=service
Shows all services (daemons managed by systemd) active on your system.
sudo systemctl restart service-name
sudo systemctl status service-name
Frequently asked questions
Why do many daemon names end in 'd'?
It's a naming convention to indicate it's this type of process, running in the background with no direct visible interface.
Can I stop any daemon without a problem?
Not always — some are essential for the system's basic operation. Research what a specific service does before stopping it, especially if you don't recognise its function.