Linux htop Command

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What is htop

htop is an interactive process viewer for Linux systems. It provides richer functionality and a more user-friendly interface than the traditional top command.

Main Features of htop

  • Color display: Different colors distinguish different types of processes and system states
  • Visual layout: Intuitively displays CPU, memory, and swap space usage
  • Mouse support: Allows direct mouse click operations
  • Process tree view: Allows viewing the hierarchical relationship of processes
  • Custom sorting: Can sort processes by various metrics
  • Process operations: Can directly kill processes, adjust priorities, etc.

Installing htop

On Debian/Ubuntu-based systems

sudo apt update
sudo apt install htop

On RHEL/CentOS-based systems

sudo yum install epel-release  # 先安装 EPEL 仓库
sudo yum install htop

On Arch Linux-based systems

sudo pacman -S htop

htop Basic Interface Explanation

To start htop, simply type in the terminal:

htop

The interface is mainly divided into the following parts:

  1. Top area: System overview information

    • CPU usage (displayed per core)
    • Memory usage
    • Swap space usage
    • System uptime and average load

  2. Middle area: Process list

    • PID: Process ID
    • USER: Process owner
    • PRI: Process priority
    • NI: Nice value
    • VIRT: Virtual memory usage
    • RES: Physical memory usage
    • SHR: Shared memory size
    • S: Process state (running, sleeping, etc.)
    • CPU%: CPU usage
    • MEM%: Memory usage rate
    • TIME+: CPU time
    • COMMAND: Command name

  3. Bottom area: Function key hints

htop Common Shortcut Keys

Shortcut key Function description
F1 or h Show help
F2 or S Enter settings menu
F3 or / Search processes
F4 or \ Filter processes
F5 or t Show process tree
F6 or < Select sort field
F7 or [ Decrease process priority
F8 or ] Increase process priority
F9 or k Kill process
F10 or q Quit htop
Space key Mark/unmark process
u Show processes of a specific user
H Show/hide user threads
K Show/hide kernel threads
P Sort by CPU usage
M Sort by memory usage
T Sort by run time

htop Advanced Features

1. Process Tree View

pressF5ortYou can switch to the process tree view, which displays the parent-child relationship between processes.

2. Process Filtering

pressF4or\You can enter filter criteria to display only processes that match the criteria.

3. Multi-select Operations

After marking multiple processes with the space bar, you can perform batch operations (such as killing).

4. Custom Display

pressF2Enter the settings menu to:

  • Adjust the displayed columns
  • Change the color theme
  • Set the refresh interval
  • Configure other display options

5. System Monitoring

The top area of htop provides rich system monitoring information:

  • CPU usage (per core)
  • Memory and swap space usage
  • System load averages

Comparison of htop and top Commands

Feature htop top
Interface Colorful, intuitive Monochrome, basic
Mouse support Yes no
Process tree view Supported Not supported
Sorting method Multiple, dynamically adjustable Limited
Process operations Richer Basic
Customization Highly configurable Limited
Resource usage Slightly higher Lower

Practical Application Examples

Example 1: Find and terminate processes with high CPU usage

  1. Start htop
  2. pressPSort by CPU usage
  3. Find the target process
  4. pressF9Choose the termination signal (usually select 15 SIGTERM)
  5. Press Enter to confirm

Example 2: Monitor a specific user's processes

  1. Start htop
  2. pressuKey
  3. Select the username to monitor
  4. Show only that user's processes

Example 3: Set the refresh interval

  1. pressF2Enter settings
  2. Select "Display options"
  3. Modify the "Delay" value (seconds)
  4. pressF10Save and exit

Frequently Asked Questions

Q1: Which is better, htop or top?

htop offers richer features and a friendlier interface, suitable for interactive use; top is more lightweight and suitable for use in scripts.

Q2: Why are some processes displayed in green/red?

Green usually indicates processes running normally; red may indicate high resource usage or zombie processes.

Q3: How do I view the full command line?

pressF2Enter settings and adjust the "Show program path" option under "Display options".

Q4: What do the memory information displayed by htop mean?

  • VIRT: Total virtual memory used by the process
  • RES: Physical memory used by the process
  • SHR: Shared memory used by the process

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