====== Memory Use ======
Check memory state of the system
<code bash>
free -m  # or top / htop
</code>

Which processes use memory?
<code bash>
top # or htop 
# Then sort by memory use (shortcut: shift+m)
</code>

Which processes use swap ?
<code bash>
# sudo aptitude install smem
sudo smem -k --sort=swap  # -k --> human readable units    , sort by swap use 
</code>