On Wed, Mar 09, 2005 at 09:54:52AM +1300, John Carter wrote:
> In the beginning, there was shell. Known to the ancient Unix guru's as the 
> program "/bin/sh".
> Since then there has been a vast proliferation of newer, and for various 
> values of the word "better", better implementations of the Command Line.
> All such programs are called "shells". csh, ash, zsh, ksh, ...
> In particular, there was one known as the Bourne Shell.

it was always my impression that the bourne shell wass the original
shell but http://en.wikipedia.org/wiki/Unix_shell calls me wrong.

> It died.

the bourne shell didn't die, but it replaced the original shell, which
is why it also is named sh. since then /bin/sh was and always will be
the bourne shell.

> Later it was revived as the Bourne Again Shell, or bash.

not revived, written from scratch and improved by the GNU project,
bourne again only refers to the fact that the bash is bourne shell
compatible and is more a play on the name. it has nothing to do with
revival of a dead bourne shell.

in different to the c-shell (csh) which is not bourne compatible and
which was a failure in the attempt to allow more c syntax like shell
scripts and mostly gained popularity because it had better interactive
features than the bourne shell
http://www.grymoire.com/Unix/CshTop10.txt
http://www.faqs.org/faqs/unix-faq/shell/csh-whynot/

the korn shell (ksh) is sh compatible and improves it and als has better
interactive features than csh.

the tenex c shell (tcsh) improves on csh naturally
(tahoe c shell is the name i learned, but
http://www.tcsh.org/tcsh.html/THE_T_IN_TCSH.html
tells a different story)

the z shell tries to be everything to everyone and is loaded with
features from both the bourne and c-shell families.

ash is a reimplementation of sh designed to be small and posix
compatible. it is used where scripts need to run but interactive
features may be given up to save space. (like boot floppies)

greetings, martin.
-- 
cooperative communication with sTeam      -     caudium, pike, roxen and unix
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pike programmer   travelling and working in europe             open-steam.org
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Martin B�hr       http://www.iaeste.or.at/~mbaehr/

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