5 Ways to check how much RAM is installed and used on CentOS 8

System engineers are often required to check memory stats in their day to day tasks. In this article, we will discuss how you can check how much RAM is installed and used on your system CentOS 8 using the command line.

There are following commands are used to check the installed system’s RAM on CentOS 8.

  1. Using /proc/meminfo
  2. Using free command
  3. Using top command
  4. Using vmstat command
  5. Using dmidecode command

Using meminfo file

Open the terminal window on your system using shortcut keys “Ctrl + Alt + t”. Type the following command on the terminal to view the Installed RAM on your system:

$ cat /proc/meminfo

Check memory usage with /proc/meminfo

In the above-mentioned output, you can see the memory of your system. The ‘cat’ is used for file concatenation.

Using free command

To check the total free memory amount, physically used and swap memory, you will use the free command. The free command is also used to display the information about buffers that are used by the kernel and specifications of the RAM of your system. Type the following command to check the system’s memory:

$ free -m -h

You can use different options with the ‘free’ command to view the system’s memory information. The general syntax is as follows:

$ free [options]

Check memory usage with free command

Command-line options of the free command

The details of more free command is given below:

–help used to display help

-b,-k,-m, and -g displays output in kilobytes, Megabytes, or Gigabytes

-l display the detailed view of statistics low and high memory

-o use for old format (cache line/no -/+buffers/)

-t shows total for RAM + swap

-s use to update delay

-c use to update count

-V use to display information about version and exit

Using top command

The top command is used to display memory and buffers information. You will run the below-mentioned command on your system to view memory information.

$ top

Get memory usage using top command

Using vmstat command

The vmstat command is used to display the memory statistics in which the user can view some additional information related to processes, block IO, traps, paging, and CPU activity. Use the following command to print statistics of memory:

$ vmstat


$ vmstat -s

Use vmstat command

Using dmidecode command

The dmidecode command is used for dumping table content of SMBIOS in a human-readable format. This table contains all the information related to the system’s hardware components and description of the serial number as well as BIOS revision. The basic syntax of the dmidecode command is as follows:

$ dmidecode --type memory

Using lshw command

The following command is used to view the memory information:

$ sudo lshw -short -C memory

Use lshw command to get details on memory usage


In this article, we have learned how to check the system’s memory on CentOS 8.0 using the command line. I hope you have really enjoyed this tutorial and it would be helpful for you. If you have any problem related to the above-mentioned commands then please let us know through feedback in the comment box.