I use a program called
xprintidle to find out the X idle time, which I'm strongly guessing uses the same data source as screensavers.
xprintidle doesn't really seem to have an upstream anymore, but the Debian package is alive and well.
It is a very simple application: it returns the amount of milliseconds since last X interaction:
$ sleep 1 && xprintidle
$ sleep 5 && xprintidle
$ sleep 10 && xprintidle
(note: due to the underlying system, it will consistently give a value in ms slightly lower than the "actual" idle time).
You can use this to create a script that runs a certain sequence after five minutes of idle time via e.g.:
# Wanted trigger timeout in milliseconds.
# Sequence to execute when timeout triggers.
echo "Triggered action $(date)"
# ceil() instead of floor()
while sleep $(((sleep_time+999)/1000)); do
if [ $idle -ge $IDLE_TIME ]; then
if ! $triggered; then
# Give 100 ms buffer to avoid frantic loops shortly before triggers.
The 100 ms offset is because of the earlier noted quirk that
xprintidle will always return a time slightly lower than the "actual" idle time when executed like this. It will work without this offset, and will then be more accurate to a tenth of a second, but it will trigger the
xprintidle check frantically during the last milliseconds before an interval end. Not a performance hog in any way, but I would find that inelegant.
I have used a similar approach in a Perl script (an irssi plugin) for quite some time, but the above was just written and has not really been tested except for a few trial runs during writing.
Try it by running it in a terminal within X. I recommend setting the timeout to e.g. 5000 ms for testing, and adding
set -x directly below
#!/bin/sh to get informative output to see how it works.