Process Management Commands in Linux

Process management commands in Linux are used to monitor, control, and manage running processes on the system. These commands help users and administrators view active processes, control execution, analyze performance, and troubleshoot system behavior efficiently.

• Used to view running and background processes
• Helps control process priority and execution
• Monitors CPU, memory, and system performance
• Essential for system monitoring and troubleshooting

The following commands are used for process management in Linux.

1. accton

The accton command is used to enable or disable process accounting. It records information about processes executed on the system.

• Tracks process execution
• Used for auditing and monitoring
• Admin-level command

Syntax:

accton file_name

Example:

accton on

• This enables process accounting.

2. bg

The bg command is used to resume a stopped job in the background. It allows processes to continue running without blocking the terminal.

• Runs jobs in background
• Used with job control
• Improves multitasking

Syntax:

bg job_id

Example:

bg %1

• This resumes job 1 in the background.

3. chrt

The chrt command is used to set or view real-time scheduling attributes of a process. It controls process priority.

• Manages scheduling priority
• Used for real-time processes
• Advanced system command

Syntax:

chrt [options] command

Example:

To see the current scheduling policy:

• Firefox is running and to find its's pid we run the following command:

$ pidof -s firefox

• In my case the pid is 5794, here is the image

Now to retrieve the current scheduling policy and priority for the firefox process, use chrt in the following way:

$ chrt -p 5794

4. fg

The fg command brings a background job to the foreground. It allows interaction with the running process.

• Moves job to foreground
• Works with job control
• Used after bg

Syntax:

fg job_id

Example:

sleep 60 &
fg %3

• This brings job 3 to the foreground.

5. kill

The kill command is used to send signals to processes. It is commonly used to terminate unresponsive processes.

• Stops running processes
• Sends signals to processes
• Essential for process control

Syntax:

kill signal pid

Example:

top 
kill 1234

• top: Shows running processes along with their process IDs, CPU usage, and memory usage in real time.
• kill 1234: Terminates the process with the process ID 1234.

6. mpstat

The mpstat command displays CPU usage statistics for processors. It helps monitor system performance.

• Displays CPU performance
• Useful for performance analysis
• Part of sysstat package

Syntax:

mpstat

Example:

mpstat

• This shows CPU usage details.

7. pidof

The pidof command displays the process ID of a running program. It helps locate processes quickly.

• Finds process ID
• Useful for scripting
• Simple and fast

Syntax:

pidof process_name

Example:

pidof bash

• This shows the PID of the bash service.

8. pmap

The pmap command displays the memory usage of a process. It helps analyze memory consumption.

• Shows memory map
• Useful for debugging
• Process analysis tool

Syntax:

pmap pid

Example:

pmap 9123

• This displays memory usage of the process.

9. ps

The ps command displays information about running processes. It shows process ID, status, and resource usage.

• Lists active processes
• Shows process details
• Common monitoring command

Syntax:

ps

Example:

ps aux

• This displays all running processes.

10. top

The top command provides a real-time view of running processes. It shows CPU and memory usage dynamically.

• Real-time monitoring
• Displays system load
• Interactive command

Syntax:

top

Example:

top

• This shows live process activity.

11. htop

The htop command is an enhanced version of top. It provides a more user-friendly and interactive interface.

• Colorful display
• Interactive process control
• Easier than top

Syntax:

htop

Example:

htop

• This displays an interactive process viewer.

12. strace

The strace command traces system calls made by a process. It is useful for debugging applications.

• Traces system calls
• Used for debugging
• Advanced diagnostic tool

Syntax:

strace command

Example:

strace ls

• This traces system calls made by ls.

13. time

The time command measures how long a command takes to execute. It displays execution time and resource usage.

• Measures execution time
• Displays CPU usage
• Useful for performance testing

Syntax:

time [options] command [arguments]

Example:

time -p sleep 3

• Real Time: The actual elapsed time, from start to finish, including time spent waiting for I/O and other processes.
• User Time: The amount of CPU time spent executing user-mode instructions within the process.
• System Time: The amount of CPU time spent executing system-level instructions on behalf of the process.

14. watch

The watch command runs a command repeatedly at fixed intervals. It is useful for monitoring changes.

• Repeats command output
• Used for monitoring
• Live updates

Syntax:

watch [options] command

Example:

watch -d free -m

• It displays total RAM, used memory, free memory, shared memory, buffer/cache usage, available memory, and swap space status

15. vmstat

The vmstat command displays memory, CPU, and I/O statistics. It provides an overview of system performance.

• Shows system statistics
• Monitors memory usage
• Performance analysis tool

Syntax:

vmstat

Example:

vmstat

• This displays system resource usage.

16. uptime

The uptime command displays how long the system has been running. It also shows system load averages.

• Shows system running time
• Displays load average
• Quick system status check

Syntax:

uptime

Example:

uptime

• This shows system uptime.

17. w

The w command displays information about logged-in users and their running processes. It combines user and process details.

• Shows logged-in users
• Displays running processes
• Useful for monitoring activity

Syntax:

w

Example:

w

• This shows active users and their processes.