-

标准输入的别名。 类似于在其他命令行工具中使用 -，这意味着脚本是从标准输入读取的，其余的选项将传给该脚本。

Alias for stdin. Analogous to the use of - in other command-line utilities, meaning that the script is read from stdin, and the rest of the options are passed to that script.