從命令響應中提取數據，並將其存儲在一個變量

Question

我想用一個腳本在啓動過程中禁用我的觸摸板這樣

#!/bin/bash

# determine device id 
ID=$(xinput list | grep -i touchpad) 

# check output 
echo $ID 

# disable device identified by $ID 
#xinput set-prop $ID "Device Enabled" 0</code> 

Basically I would like to extract "12" (or whatever number the device has) from the result of command:

• xinput list | grep -i touchpad
  ⎜ ↳ SynPS/2 Synaptics TouchPad id=12 [slave pointer (2)]

and store it in variable $ID.

The next command would disable the device.

Any suggestions on how I can achieve that?

Thanks, Udo

Answer 1

If you know the output of xinput list將始終具有ID號作爲第5場，然後使用：

ID=$(xinput list | awk -F'[= ]' '/TouchPad/{print $5}') 

如果你寧願鍵關機字id=使得它可以在任何地方就行了，然後使用：

ID=$(xinput list | sed '/TouchPad/s/^.*id=\([0-9]*\).*$/\1/') 

Answer 2

GNU grep：

ID=$(xinput list | grep -Poi '(?<=touchpad[[:blank:]]*id=)[0-9]+') 

GNU sed：

ID=$(xinput list | sed -n 's/.*touchpad[[:blank:]]*id=\([0-9]\+\)[[:blank:]]*.*/\1/Ip')