Linux Swap Usage Oneliner with numerical only output

Question

I'd like to get a Linux bash one liner which will echo out the current SWAP in use (can be in kB, KB, MB). I only need the numbers, no text descriptions or any of the other RAM information... tried using Google, but it seems no one has requested this before.

A 2 - 5 line script would work as well, though I'll favor a one-liner...

Answer 1

This one liner will give the used swap based on subtracting the free swap from the total swap:

grep -E '^Swap[TF]' /proc/meminfo | awk 'p{print p-$2}{p=$2}'

The grep extracts the relevant lines from /proc/meminfo and the awk subtracts the two values.

edit: removed a $3 from the end of the awk print statement as the OP stated they just wanted the number. This number will be in KB.