An example hook script to verify if you are on battery, in case you are running Linux or OS X. Called by git-gc –auto with no arguments. The hook should exit with non-zero status after issuing an appropriate message if it wants to stop the auto repacking.
#!/bin/sh if test -x /sbin/on_ac_power && /sbin/on_ac_power then exit 0 elif test "$(cat /sys/class/power_supply/AC/online 2>/dev/null)" = 1 then exit 0 elif grep -q 'on-line' /proc/acpi/ac_adapter/AC/state 2>/dev/null then exit 0 elif grep -q '0x01$' /proc/apm 2>/dev/null then exit 0 elif grep -q "AC Power \+: 1" /proc/pmu/info 2>/dev/null then exit 0 elif test -x /usr/bin/pmset && /usr/bin/pmset -g batt | grep -q "drawing from 'AC Power'" then exit 0 elif test -d /sys/bus/acpi/drivers/battery && test 0 = \ "$(find /sys/bus/acpi/drivers/battery/ -type l | wc -l)"; then # No battery exists. exit 0 fi echo "Auto packing deferred; not on AC" exit 1