+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 which on_ac_power >/dev/null 2>&1; then
+ on_ac_power
+ POWER=$?
+ if [ $POWER -eq 1 ]; then
+ debug_echo "exit: system NOT on main power"
+ return 1
+ elif [ $POWER -ne 0 ]; then
+ debug_echo "power status ($POWER) undetermined, continuing"
+ fi
+ debug_echo "system is on main power."
+ fi
+ return 0
+}
+