join(1) on Linux
The text 64d83b56294d, as Debian 1.1 (Buzz) shipped it.
join lines of two files on a common field
Flags it lists
-
--help -
--version -
-1 -
-2 -
-a -
-e -
-j -
-j1 -
-j2 -
-o -
-t -
-v