comm reads two files
file1 and
file2 which should be ordered in the collating sequence of the current locale,
and produces three text columns as output:
- 1
- Lines only in file1.
- 2
- Lines only in file2.
- 3
- Lines in both files.
If lines in either file are not ordered according to the collating sequence of the current locale, the results are not specified.
If either file1 or file2 is -, comm uses standard input starting at the current location.