------

#!/bin/bash
echo ‘Hello World!‘

array=(a b 3 "ch")
for i in array;do
    echo ${array[i]}
done

echo ${array[*]}
echo ${#array[@]}
#---------------------------------------
vers=$(uname -r) #括号表示括号里面的内容先执行 等同于反引号
echo ${vers}
read -p "input your name: " -t 30 named
#----------------------------------------
val=$((2+2))
echo "两数之和为 : $val"

#输出==========================================================================
Hello World!
a
a b 3 ch
4
3.13.0-32-generic
两数之和为 : 4