I have been a happy i3wm user since 2012.
A problem I faced early on was that I would often forget to connect my laptop’s charger so it would eventually shut down. Even though i3status can display the current battery level, I have found that it is very easy to miss.
After many unexpected reboots, I decided to write a simple Bash script that displays a notification when the battery level percentage reaches or drops below a configured threshold:
#!/usr/bin/env bash THRESHOLD=10 lock_path='/tmp/batmon.lock' lockfile-create -r 0 -l $lock_path || exit acpi_path=$(find /sys/class/power_supply/ -name 'BAT*' | head -1) charge_status=$(cat "$acpi_path/status") charge_percent=$(acpi | cut -d ' ' -f 4 | sed 's/[^0-9]//g') if [[ $charge_status == 'Discharging' ]] && [[ $charge_percent -le $THRESHOLD ]]; then message="Battery running critically low at $charge_percent%!" DISPLAY=:0.0 /usr/bin/notify-send -u critical 'Low battery' "$message"fi rm -f $lock_path
Some things to note:
- The threshold percentage is configurable
- The script will exit if it’s already running to avoid multiple notifications e.g. when run by Cron
- A notification is shown using notify-send (ships with libnotify-bin on Debian)
I run the script every minute with Cron by placing the following under
* * * * * agorf eval "export $(egrep -z DBUS_SESSION_BUS_ADDRESS /proc/$(pgrep -ou agorf dbus-daemon)/environ)"; bash ~/work/scripts/batmon.sh