合并Linux上的两个文件，只保留两个文件中出现的行

Question

In Linux, how can I merge two files and only keep lines that have a match in both files?

Each line is separated by a newline ( \\n ).

So far, I found to sort it, then use comm -12 . Is this the best approach (assuming it's correct)?

fileA contains

aaa
bbb
ccc
ddd

fileB contains

aaa
ddd
eee

and I'd like a new file to contain

aaa
ddd

Answer 1

Provided both of your two input files are lexicographically sorted , you can indeed use comm :

$ comm -12 fileA fileB > fileC

If that's not the case, you should sort your input files first:

$ comm -12 <(sort fileA) <(sort fileB) > fileC