Join (Unix)

join
Original author(s)	Douglas McIlroy
Developer(s)	AT&T Bell Laboratories
Initial release	January 1979
Written in	C
Operating system	Unix, Unix-like, Plan 9
Platform	Cross-platform
Type	Command
License	coreutils: 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.