🔌 upower是GNU/Linux系统中用于枚举电源设备、监听设备事件以及查询历史和统计数据的抽象工具，支持列出所有电源设备并获取详细信息。

📊 使用--dump (-d)选项可以列出所有电源设备及其路径，而--show-info (-i)选项则需要提供设备路径来获取特定设备的详细信息，如电池百分比、状态等。

🔍 通过结合awk和grep等命令，可以高效地从upower输出中提取所需信息，例如仅显示电池百分比或一次性列出所有电池的关键状态信息。

📈 文章提供了一个shell脚本示例，该脚本可以自动化获取电池的百分比、容量、更新时间和空电时间等数据，方便用户进行电源管理自动化或特定程序开发。

UPower is an abstraction for enumerating power devices, listening to device events and querying history and statistics. Using the upower command-line tool on GNU/Linux, you can get information about your power sources like the batteries your wireless mouse or laptop, and see their battery levels.

In this article, let's see how we can gather such information and use in a script.

How to use upower

First of all, list your power sources with the --dump, -d flag :

$ upower -d

If you have multiple power sources and want to show information about only one of them, you need to copy the device path starting with /org/freedesktop/UPower/devices of your target power source from the output of the previous command.

You need to pass that path using the --show-info, -i flag. For my laptop battery, I use the command below:

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

Or I could use the below command to only see the battery percentage:

$ upower -i /org/freedesktop/UPower/devices/battery_BAT0 | awk '/percentage/' {print $NF}'87%

With awk, we can extract the desired information like above. Here's one another example with the grep command to list all the information at once:

$ upower -i $(upower -e | grep 'BAT') | grep -E "state|to\ (full|empty)|percentage"

Note that the above command is only good when you want to print some data in the terminal. For an advanced alternative, keep reading.

Extract and show battery information in a script

You may want to use the battery percentage or similar information in a shell script to make some automations or specific programs. If you have such goal, you can find a simple script I wrote below:

#!/bin/bash### Author: Can ELMA### Website: https://elma.dev### This script is intended to be used to show information about power sources.# YOU CAN EDIT THE LINES BELOWDEFAULT_DEVICE_NAME='battery_BAT0'# YOU CAN EDIT THE LINES ABOVE# ! DO NOT EDIT VARIABLES BELOW ! #DEVICE_NAME=${1:-'battery_BAT0'}PATH_PREFIX='/org/freedesktop/UPower/devices'DEVICE_PATH="$PATH_PREFIX/$DEVICE_NAME"# ! DO NOT EDIT VARIABLES ABOVE ! #if [ $# -gt 1 ]; then  echo "Only one parameter is allowed."  echo "Usage: '$0 <optional:device_name>'"  exit 1fi# GATHER INFORMATION ABOUT THE BATTERY DEVICEINFORMATION=$(upower -i "$DEVICE_PATH" 2> /dev/null)PERCENTAGE=$(awk '/percentage/ {print $NF}' <<< $INFORMATION)CAPACITY=$(awk '/capacity/ {print $NF}' <<< $INFORMATION)UPDATED=$(awk -F '(' '/updated/ {print $NF}' <<< $INFORMATION | sed -r 's/\)//')TIME_TO_EMPTY=$(awk -F ':' '/time to empty/ {print $NF}' <<< $INFORMATION | sed -r 's/\s{2,}//g')print_info() {  [ $# -ne 2 ] && echo "print_info() requires two parameters." && exit 1  printf "%s\t%s\n" "$1" "$2"}print_info "percentage:" "$PERCENTAGE"print_info 'capacity:' "$CAPACITY"print_info 'updated:' "$UPDATED"print_info 'time to empty:' "$TIME_TO_EMPTY"

You can change the default device name to the name of your power source by renaming the DEFAULT_DEVICE_NAME variable, or can pass that information to the script as an argument. Paste the codes above to a file named battery. With the chmod +x ./battery command, make it executable.

Usage:

$ ./batterypercentage:     37%capacity:       75.4833%updated:        44 seconds agotime to empty:  2.8 hours

or

$ ./battery battery_BAT0percentage:     92%capacity:       84.1224%updated:        46 seconds agotime to empty:  5.9 hours

That's all.