How to Change the htop Update Interval?

The htop command-line utility is a powerful, interactive system monitor for Linux that provides a real-time view of processes, CPU usage, and memory consumption. By default, htop refreshes its metrics every 2 seconds, but this frequency can be easily adjusted to suit your monitoring needs. This article explains how to configure the update delay interval using two primary methods: passing a command-line flag upon launch, or modifying the delay dynamically from within the interactive interface.

Method 1: Using the Command-Line Delay Flag

The quickest way to launch htop with a custom refresh rate is by using the -d (delay) command-line flag. This flag accepts an integer representing the update interval in tenths of a second.

To use this method, open your terminal and append the delay value to the command:

htop -d [value]

For example, if you want htop to refresh every 5 seconds, you would multiply 5 by 10 and enter 50 as the value:

htop -d 50

Conversely, if you need high-frequency tracking and want the data to update every half-second (0.5 seconds), you would pass a value of 5:

htop -d 5

Method 2: Adjusting the Delay Inside htop

If htop is already running, you do not need to close the program to change how fast the data refreshes. You can use standard keyboard shortcuts to alter the delay interval on the fly.

• Increase the delay: Press the + key (or Shift + = on some keyboards) to slow down the refresh rate, adding more time between updates.
• Decrease the delay: Press the - key to speed up the refresh rate, forcing htop to update system metrics more frequently.

Each keypress adjusts the update interval by one-tenth of a second, allowing for precise control over system resources while monitoring.