Larry McVoy on 30.12.2022 21:02:

> [SysIII port]

Is there are reason to hang on to the Bourne shell?  Maybe shell scripts?
Does it perform better than ksh or bash?

Don't get me wrong, I much prefer the sh syntax over csh syntax, but 
I'd never go back to the Bourne shell as my login shell.  Way too much
useful stuff in ksh/bash.

I'd like the idea of   "preserving a heirloom in its natural environment"
(and even more effort went in https://heirloom.sourceforge.net/sh.html)
let alone this does not prevent from adding modern shells...

I guess in interactive use most users would only miss one thing: the history & line editing capability?

Side notes to that:

• By intention, the almquist shell (a port due to the Berkeley/ATT mess) initially had no history. From the package file DIFFERENCES [1],
  
  "History.   It seems to me that the csh history mechanism is mostly a response to the deficiencies of UNIX terminal I/O. Those of you running 4.2 BSD should try out atty (which I am posting to the net at the same time as ash) and see if you still want history."

• and in "ksh - An Extensible High Level Language" David Korn writes:
  
  "Originally the idea of adding command line editing to ksh was rejected in the hope that line editing would move into the terminal driver." [2]
  

I have always wondered, what such a central terminal driver driven history/line-editing would have felt like.

[1] https://www.in-ulm.de/~mascheck/various/ash/DIFFERENCES
[2] https://www.in-ulm.de/~mascheck/bourne/korn.html