Title: ps, top and free Commands
Course: CIS 121: Linux/UNIX I: Fundamentals ~ For IGNITE Review > Section: Learning Modules

ps Command

The ps command can be used to list processes.

Options:

- -u followed by a username, lists that user's processes.
- --forest shows child-parent relationships.
- -e shows every process.
- -f shows fuller line of information.

top Command

The top command can be used to check the load on a system and list processes.

- Information is sorted by CPU usage.
- ? or h will display command information.
- Use q to exit.

free Command

The free command can be used to measure memory usage.

- Memory usage can impact performance.
- Watch for problems like memory leaks.
- Watch for use of swap space.
- Example: free -m