Compare sorted files FILE1 and FILE2 line by line.

With no options, produce three-column output. Column one contains lines unique to FILE1, column two contains lines unique to FILE2, and column three contains lines common to both files.

-1

suppress lines unique to FILE1

-2

suppress lines unique to FILE2

-3

suppress lines that appear in both files

--help

display this help and exit

--version

output version information and exit

info comm

should give you access to the complete manual.