#!/bin/sh
set -e
# Systemd systems use a systemd timer unit which is preferable to
# run. We want to randomize the apt update and unattended-upgrade
# runs as much as possible to avoid hitting the mirrors all at the
# same time. The systemd time is better at this than the fixed
# cron.daily time
if [ -d /run/systemd/system ]; then
exit 0
fi
check_power()
{
# laptop check, on_ac_power returns:
# 0 (true) System is on main power
# 1 (false) System is not on main power
# 255 (false) Power status could not be determined
# Desktop systems always return 255 it seems
if command -v on_ac_power >/dev/null; then
if on_ac_power; then
:
elif [ $? -eq 1 ]; then
return 1
fi
fi
return 0
}
# sleep for a random interval of time (default 30min)
# (some code taken from cron-apt, thanks)
random_sleep()
{
RandomSleep=1800
eval $(apt-config shell RandomSleep APT::Periodic::RandomSleep)
if [ $RandomSleep -eq 0 ]; then
return
fi
if [ -z "$RANDOM" ] ; then
# A fix for shells that do not have this bash feature.
RANDOM=$(( $(dd if=/dev/urandom bs=2 count=1 2> /dev/null | cksum | cut -d' ' -f1) % 32767 ))
fi
TIME=$(($RANDOM % $RandomSleep))
sleep $TIME
}
# delay the job execution by a random amount of time
random_sleep
# ensure we don't do this on battery
check_power || exit 0
# run daily job
exec /usr/lib/apt/apt.systemd.daily
Mini Shell