在Linux下自己实现文件打开功能，相当于more，cat的功能，还有附加的功能，可输出打开文件的行数，以及可根据用户命令输出指定的行数。-In their own files under the Linux open the function, which is equivalent to more, cat s features, as well as additional features, can be exported to open the file number of rows,