shell 字符串相关判断

shell 字符串相关判断

	#!/usr/bin/env bash
	
	set -e
	
	a="abc"
	b="efg"
	
	if [ $a = $b ];
	then
	   echo "$a = $b : a 等于 b"
	else
	   echo "$a = $b: a 不等于 b"
	fi
	
	if [ $a != $b ];
	then
	   echo "$a != $b : a 不等于 b"
	else
	   echo "$a != $b: a 等于 b"
	fi
	
	if [ -z $a ];
	then
	   echo "-z $a : 字符串长度为 0"
	else
	   echo "-z $a : 字符串长度不为 0"
	fi
	
	if [ -n "$a" ];
	then
	   echo "-n $a : 字符串长度不为 0"
	else
	   echo "-n $a : 字符串长度为 0"
	fi
	
	if [ $a ];
	then
	   echo "$a : 字符串不为空"
	else
	   echo "$a : 字符串为空"
	fi