Ancestry of Unix-like shells
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Shell ancestry

A history (ahem) of command shells in Unix and Unix-like systems.

Each shell appears at the year that it was first announced to the world. For example, S. R. Bourne describes his shell in the Bell System Technical Journal in 1978 but Bell released it to the world in 1979 or so.

A shell uses a solid, black arrow to point to a shell that it borrows source code from. A shell uses a dashed, grey arrow to point to a shell that the former attempts to be compatible with while not using the latter's source code.

A plum-coloured shell has an open, free, or public license.

A green shell had a proprietary or closed license at the time that it was announced. Source for many formerly-closed shells are now available for us to look at. For example, Bell Labs released to source code to UNIX, available in a few links below.

The authors of a shell are the people credited at the time of the shell's announcement.

Shell ancestry

Almquist shell

Author: Kenneth Almquist

Also known as ash.


Author: Brian Fox

Bourne shell

Author: S. R. Bourne

BRL shell

Authors: Doug A Gwyn, Doug Kingston, Ron Natalie, Arnold Robbins, Lou Salkind, and others?


Author: Bruce Perens

C shell

Author: Bill Joy

Desktop KornShell

Author: Stephen J. Pendergrast

Also known as dtksh

Forsyth shell

Author: Charles Forsyth

I've corresponded with Charles Forsyth. He tells me that he adapted his shell for MINIX 1 too.

es shell

Authors: Paul Haahr, Byron Rakitzis

Korn shell, ksh88, ksh93, ksh93q

Author: David G. Korn


Author: ?

Public Domain Korn shell, OpenBSD ksh

Author: Eric Gisin

PWB shell

Author: John Mashey

Programmer's Work Bench shell, aka Mashey shell!original/net.unix-wizards/k1FW4s0X7jw/4GNAGTPHLXQJ

rc shell

Author: Tom Duff

Thompson shell

Author: Ken Thompson


Authors: Ken Greer, Paul Placeway, Christos Zoulas, et al.!msg/net.sources/BC0V7oosT8k/MKNdzEG_c3AJ



Author: Robert Landley


Author: Paul Falstad!msg/alt.sources/tVgN49u8Ax4/7VgQlHZ4bJMJ