In this tutorial, we will see how to use the terminal to clean up unused memory that was not released properly after being used by your system. No need to use any third-party software, just a few commands will do the job pretty easily.

Check Memory Usage in Real-Time

You can check your current memory usage using this command:

watch -n 1 free -m

This command will also display in real-time your system memory usage:

watch -n 1 cat /proc/meminfo

In the returned outputs, focus on these memory details:

  • MemTotal:        1027104 kB
  • MemFree:          302836 kB
  • Buffers:           24212 kB
  • Cached:           297364 kB
  • SwapCached:            0 kB
  • Active:           478336 kB
  • Inactive:         164844 kB
Free Up Unused Memory

   Command 1

You can free up unused memory under Ubuntu/Linux Mint using this command:

sudo sysctl -w vm.drop_caches=3

NOTE: this action won't make your system faster nor it will affect its stability and performance, it will just clean up memory used by the Linux Kernel on caches.

   Command 2

Here is another command that can help you free up memory either used or cached (page cache, inodes, and dentries):

sudo sync && echo 3 | sudo tee /proc/sys/vm/drop_caches

NOTE: You can use cron jobs to schedule the commands above to run at specific time intervals.

If you have more useful commands for releasing/flushing memory in Ubuntu/Linux Mint, use the comment form below.