bash 初探

#!/usr/bin/bash
echo "hello world!!"
num=100
PI=3.14
STR="hello"
str_2='world!'

echo ${num}
echo ${PI}
echo ${STR}
echo ${str_2}

x=$[$num-50]
echo $x
echo ${x}

array[1]=$num
array[2]=$PI
echo ${array[2]}
exit 0