This question already has answers here: Get selected element's outer HTML (30 answers) Closed 7 years ago.
目录Bash Shwww.devze.comell 判断一个变量是否为空检查bash shell变量是否为空的另一个方式您可以将 -z 选项传递给 if 命令或条件表达式。如果STRING的长度为0,variable ($var)为空。test命令用于检查文件类型并比较