shell脚本之逻辑判断

#!/bin/bash
a=10
b=20
if [[ $a -lt 100 && $b -gt 100 ]]
then
        echo "right"
else
        echo "wrong"
fi
if [[ $a -lt 100 || $b -gt 100 ]]
then
        echo "right"
else
        echo "wrong"
fi

输出
wrong
right

注意if后面空格一定不能少

if [ $a -lt 100 -o $b -gt 100 ]
then
        echo "right"
else
        echo "wrong"
fi

if [ $a -lt 100 -a $b -gt 100 ]
then
        echo "right"
else
        echo "wrong"
fi
if [ $a != $b ]
then
        echo "right"
else
        echo "wrong"
fi

输出 
right
wrong 
right