free up memory in linux code example

Example 1: linux memory cache clear

# clear pagecache only.
sync; echo 1 > /proc/sys/vm/drop_caches

# clear dentries and inodes.
sync; echo 2 > /proc/sys/vm/drop_caches

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

Example 2: clear ram cache ubuntu

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

Example 3: linux how to free memory

echo 2 > /proc/sys/vm/drop_caches