@@ 31,6 31,16 @@ All lines in both files must be pre-sorted character-wise.
Suppress the output of lines common to both files.
# UNSPECIFIED BEHAVIOR
The POSIX standard does not unambiguously specify the behavior of this command
under certain conditions. Under such conditions, the ctools implementation of
*comm* behaves as follows:
- If either file is not sorted, *comm* exits with an error.
- If both _file1_ and _file2_ refer to standard input or to the same FIFO
special, block special, or character special file, *comm* exits with an error.
This command is part of ctools and is compatible with POSIX-1.2017, and may