Bash 11-13

Lesson 11: Correcting Laptop Insomnia
cat /proc/acpi/button/lid/LID/state #会返回电脑是否开着的信息
cat /sys/class/power_supply/AC/online #返回电脑电源或电池是否插着
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#!/bin/bash

grep -q closed /proc/acpi/button/lid/LID/state
#-q (quite,只检查，不做任何事),检查state文件里面有没有“closed“
if [ $? = 0 ] #检查之前一条代码的输出是true
then
## The laptop lid is closed, let’s find out if it’s plugged in.
grep -q 0 /sys/class/power_supply/AC/online
if [ $? = 0 ]
then
## The laptop is not plugged in. It should be asleep.
pm -syspend
fi
end

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Lesson 12: Filesystem Locations For Bash Script（把代码保存在哪？）

• pwd #present working directory目前工作目录
• echo $PATH #运行脚本的时候会自动查找的path，如果脚本在这些path下，在任何工作目录下都可以运行它们
• #/usr/local/bin(for everybody)和/usr/local/sbin(only for root)可以用来存储代码，存在这两个文件里面的代码，在任何目录下都可运行
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• 可以在home directory建立文件夹bin，并将其加入echo $PATH自动查找path
• nano ~/.bash_profile
  PATH=$PATH:$HOME/bin
  export PATH
  ^o #保存文件
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• sudo cp whiletest /usr/local/bin #将文件copy到某处，由于要从home copy的话，必须用sudo
• ./ #在当前目录下运行某代码

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Lesson 13：The case statement
nano turtles
#!/bin/bash
echo “What is your favorite Ninja Turtle?”
echo “1 - Raphael.”
echo “2 - Leonardo.”
echo “3 - Michelangelo”
echo “4 - Donatello.”
read turtle;
case $turtle in
1) echo “Raphael is cool, but rude.”;; # ‘)’和’;;’是固定格式
2) echo “Leonardo leads.”;;
3) echo “Michelangelo is a party dude.”;;
4) echo “Donatello does machines.”;;
*) echo “Did you even watch the show?”
esac

chmod +x turtles