how to free RAM memory linux code example

Example 1: clear ram linux

sudo sync; echo 3 > /proc/sys/vm/drop_caches

Example 2: how to clear memory in ubuntu 18.04

# Clear PageCache, dentries and inodes.
sync; echo 3 > /proc/sys/vm/drop_caches

Example 3: linux how to free memory

echo 2 > /proc/sys/vm/drop_caches

Example 4: how to clear memory in ubuntu 18.04

sync; echo 1 > /proc/sys/vm/drop_caches