htop command in Linux with examples

htop command in Linux system is a command line utility that allows the user to interactively monitor the system’s vital resources or server’s processes in real-time. htop is a newer program compared to top command, and it offers many improvements over top command. htop supports mouse operation, uses color in its output, and gives visual indications about processor, memory, and swap usage. htop also prints full command lines for processes and allows one to scroll both vertically and horizontally for processes and command lines respectively.

Syntax

htop 

This will open an interactive interface showing all running processes, along with CPU, memory, and swap usage. You can also specify options when launching htop.

Basic Example:

Common Options used with htop command

Here are some of the most commonly used options with htop:

htop command Examples in Linux

1. htop -d <delay>:

htop -d 10 means shows delay between screen updates in 1 second. If you give delay as 15 means delay of 1.5 sec, similarly 23 means 2.3 sec etc. This delay is useful as it reduce frequent updates.

2. htop -u <username>:

Used to show only the processes of a given user. Here it is:

htop -u kunwarvikas

3. htop -p <pid>:

Used to show only the given PIDs.

4. htop -s <column>:

Sorts the given column.

5. htop -t:

Displays the process hierarchy in tree view in the commands column.

6. htop -no-color:

Disables color.

7. -v --version:

Output version information and exit.

Interactive Commands

• Arrows, Page Up, Page Down, Home, End: Scroll the process list.
• Space: Tag or untag a process.
• U - Untag all processes (remove all tags added with the Space key).
• s - Trace process system calls.
• F1 - Help
• F2 - setup
• F3 - search
• F4 - filtering: type in part of a process command line and only processes whose names match will be shown.
• F5 - Tree view.
• F6 - Sorting.
• F7 - Increase the selected process's priority. This can only be done by the superuser.
• F8 - Decrease the selected process's priority.
• F9 - Kill process.
• F10 - Quit.

Conclusion

The htop command is a powerful tool for monitoring and managing system processes in real-time. With its interactive interface and advanced features like sorting and filtering, it will be beneficial for system administrators and users who want a detailed view of system performance.