The join command has been around for over 30 years! See p. 7 of this PDF (which contains SunOS 4.1.2 manual pages): http://www.bitsavers.org/pdf/sun/sunos/4.1.

The join command has been around for over 30 years! See p. 7 of this PDF (which contains SunOS 4.1.2 manual pages): http://www.bitsavers.org/pdf/sun/sunos/4.1.2/800-6641-10_Reference_Manual_Pages_for_SunOS_4.1.2_199112.pdf http://www.bitsavers.org/pdf/sun/sunos/4.1.2/800-6641-10_Ref... The short description it gives for the command is "relational database operator". (The "Last change: 4 March 1988" at the bottom of the page refers to the last change of the intro(1) manual page, not the whole book.)