Join (Unix)

join
Original author(s)Douglas McIlroy
Developer(s)AT&T Bell Laboratories
Initial releaseJanuary 1979; 45 years ago (1979-01)
Written inC
Operating systemUnix, Unix-like, Plan 9
PlatformCross-platform
TypeCommand
Licensecoreutils: GPLv3+
Plan 9: MIT License

join is a command in Unix and Unix-like operating systems that merges the lines of two sorted text files based on the presence of a common field. It is similar to the join operator used in relational databases but operating on text files.