join(1) on Linux
The text ef02308a082f, as Debian 7 (Wheezy) shipped it.
join lines of two files on a common field
Flags it lists
-
--check-order -
--header -
--help -
--ignore-case -
--nocheck-order -
--version -
-1 -
-2 -
-a -
-e -
-i -
-j -
-o -
-t -
-v