Vimdiff - 如何在文件中提取相似的行并将它们输出到文件中

I am new to vimdiff and had a question about outputting the similarities of the two or more files into a new file. For example, based on the following picture I would like to have b,c,e,f,a along with the names of the two files being compared outputted to a different file.I am new to vimdiff and had a question about ou