title: Know how much swap is used by each process on Linux
body: <p>I use the following script (from this blog <a href="http://northernmost.org/blog/find-out-what-is-using-your-swap" rel="nofollow">http://northernmost.org/blog/find-out-what-is-using-your-swap</a>) to know for each process how much swap it is using</p>
  
  <pre><code>#!/bin/bash
  # Get current swap usage for all running processes
  # Erik Ljungstrom 27/05/2011
  SUM=0
  OVERALL=0
  for DIR in `find /proc/ -maxdepth 1 -type d | egrep "^/proc/[0-9]"` ; do
  PID=`echo $DIR | cut -d / -f 3`
  PROGNAME=`ps -p $PID -o comm --no-headers`
  for SWAP in `grep Swap $DIR/smaps 2&gt;/dev/null| awk '{ print $2 }'`
  do
  let SUM=$SUM+$SWAP
  done
  echo "PID=$PID - Swap used: $SUM - ($PROGNAME )"
  let OVERALL=$OVERALL+$SUM
  SUM=0
  
  done
  echo "Overall swap used: $OVERALL"
  </code></pre>
  
  <p>The overall swap used output by this script does not match the swap used output by the <strong><em>free</em></strong> command.</p>
  
  <p>Is anybody able to explain why ?</p>