====== Ubuntu - Swap - Clear swap ======

===== Check your swap usage =====

<code bash>
free -m

                    total       used       free     shared    buffers     cached

Mem:          1024        157        866          0         11         48

-/+ buffers/cache:         97        926

Swap:          127         95         32
</code>

where 

  * **-m** is for the value to be listed in megabytes.

----

===== To clear the swap =====

<code bash>
sync && /sbin/sysctl vm.drop_caches=3 && swapoff -a && swapon -a 
</code>

where 

  * **sync** is to force changed blocks to disk and update the super block; 
  * **sysctl vm.drop_caches=3** is to free pagecache, dentries and inodes; 
  * **swapoff** is to turn off swap;
  * **swapon** is to turn swap back on.


----

===== Check the swap again =====

<code bash>
free -m

                    total       used       free     shared    buffers     cached

Mem:          1024        157        866          0         11         48

-/+ buffers/cache:         97        926

Swap:          127         0         127
</code>