Linux Tutorial
Processes and Services
Inspect running processes, signals, jobs, resource usage and service state.
Concept
A process is a running program with an identifier. ps and top-like tools help inspect processes, while signals request actions such as termination or reload.
On many modern distributions, systemd manages long-running services. Check status and logs before restarting a failing service so you preserve useful diagnostic evidence.
Example
ps aux | head
ps -ef | grep ssh
# On systemd-based distributions:
systemctl status ssh
Type the example yourself and change at least one value. Small experiments reveal syntax and behavior faster than passive reading.
Practice Tasks
- Find your shell process ID.
- Start a long-running command in the background and inspect it with jobs.
- Check the status of an installed service.
Key Takeaways
- Processes have IDs and state.
- Signals control processes.
- Inspect service status and logs before changing things.