CRON作业和bash脚本以检查电池状态和蜂鸣声

Question

I recently changed desktop environments and the new one doesn't have a battery monitor. I had managed to create a simple manual one by doing the following:

alias bat='upower -i /org/freedesktop/UPower/devices/battery_BAT0| grep -E "state|to\ full|percentage"'

I would like to take this to the next level and create a script that not only checks the battery level but also beeps according to it, lets say it will beep if the battery percent is less then 20%. I would then like to run it as CRON job, which lets say will run every 5 minutes.

I also used the following to create a beep sound which I liked:

alias beep='paplay /usr/share/sounds/ubuntu/stereo/message-new-instant.ogg'

Assuming the CRON part is covered, how would you write this script in bash, assuming you use the same command as used in 'bat':

upower -i /org/freedesktop/UPower/devices/battery_BAT0

thanks

Answer 1

I came up with the following solution:

1) Create a bash script:

#!/bin/bash

bat='upower -i /org/freedesktop/UPower/devices/battery_BAT0| grep -E "state|to\ full|percentage"'
beep='paplay /usr/share/sounds/ubuntu/stereo/message-new-instant.ogg'

# This gets the integer percentage of current battery capacity
p=$(eval $bat | grep 'percentage' | awk '{print $2}' | awk -F '.' '{print $1}')

# if bat < 25% -> BEEP once
if [ "$p" -le 25 ] ; then
    eval $beep
fi

2) Set the permissions:

chmod 700 /path/to/script.sh

3) To set a cron job run crontab -e and add the following line:

*/1 * * * * /path/to/script.sh

which means the script will be run every minute.