The function then grabs every line in the current file (getline(1,'$')) and calls the built-in writefile() function to write them to disk.

函数随后获取当前文件（getline(1,'$')）中的每一行并调用内置的 writefile() 函数来将它们写入到磁盘中。

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The second argument to writefile is the name of the new file to be written; in this case, the name of the current file (bufname (' % ')) with the counter's new value appended.

writefile的第二个参数是将要写入的新文件的名称；在本例中，为当前文件(bufname(' % '))的名称附加上计数器的新值。

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