Monitor system processes using commands like ps, top, and htop.

Jorge is studying for his LFCS exam on his RHEL Server. He wants to master ps, top, and htop: Monitor system processes using commands like ps, top, and htop.

Please give Jorge several command examples that will help him to master this objective.

Certainly! Here are several command examples that Jorge can use to monitor system processes using ps, top, and htop on his RHEL Server:

1. ps aux: Displays a list of all running processes on the system, including detailed information such as the process ID (PID), CPU and memory usage, and the command associated with each process.

2. ps -ef: Provides a detailed listing of all running processes, including the process tree and associated information like user, PID, parent process ID (PPID), CPU usage, etc.

3. top: Launches an interactive real-time system monitoring tool that displays a dynamic view of system processes, CPU usage, memory usage, and other system statistics. Pressing 'q' will exit the top command.

4. htop: Similar to top, htop is an interactive process viewer with more advanced features and a user-friendly interface. It provides a detailed view of system processes, resource utilization, and allows sorting and filtering processes. Pressing 'q' will exit htop.

5. top -n 1 -b: Runs top in batch mode, which outputs a one-time snapshot of system processes and resource usage in a non-interactive format. The -n 1 option specifies a single iteration, and -b stands for batch mode.

6. htop --sort-key PERCENT_CPU: Launches htop with the process list sorted by CPU usage in descending order. This helps identify the most CPU-intensive processes at the top of the list.

7. ps -e --forest: Displays a process tree, showing the hierarchical relationship between processes. Child processes are indented under their parent processes, making it easier to visualize process dependencies.

8. ps -p <PID> -o pid,ppid,cmd,%cpu,%mem: Retrieves specific information for a given process ID (replace <PID> with the actual process ID). It displays the PID, PPID, command, CPU usage (%CPU), and memory usage (%MEM) of the process.

9. ps -u <username>: Lists all processes owned by a specific user (replace <username> with the desired username). This helps in monitoring the processes associated with a particular user.

10. top -d <seconds>: Sets the refresh interval for top (replace <seconds> with the desired interval in seconds). This allows top to update its display at regular intervals, providing real-time monitoring of system processes.

These commands will provide Jorge with a good starting point to monitor system processes using ps, top, and htop on his RHEL Server. He can explore further options and flags available for these commands through their respective man pages (man ps, man top, man htop).