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From: belmonte@svax.cs.cornell.edu (Matthew Belmonte)
Newsgroups: comp.sys.m6809
Subject: Re: Is there anything better than the standard shell?
Message-ID: <1808@svax.cs.cornell.edu>
Date: Wed, 18-Nov-87 18:42:13 EST
Article-I.D.: svax.1808
Posted: Wed Nov 18 18:42:13 1987
Date-Received: Sat, 21-Nov-87 11:05:40 EST
References: <1792@utx1.UUCP>
Reply-To: belmonte@sleepy.cs.cornell.edu (Matthew Belmonte)
Followup-To: comp.sys.m6809
Organization: Cornell Univ. CS Dept.
Lines: 30
Keywords: shell coco
Summary: clarification

In article <1792@utx1.UUCP> davis@utx1.UUCP (Gary A. Davis) writes:
>Is there any better SHELL available for OS9 LII (CoCo) than the one supplied?
>I would like to have a few of the features I have come to appreciate in the
>UNIX ksh such as history and wild-card expansion. Other nice things would be
>environment variables (especially PATH with an appropriate fork that would
>search the path).

a clarification - the fork syscall doesn't search the path.  the shell looks
up the correct path for a given program name and hands the full path name to
fork (or, more precisely for UNIX, forks and then hands the full path name to
execve).  i don't know much about level 2 (it's been about a year since i've
fired up my old level 1 system), but it seems that if you have source code or a
good disassembler or debugger, it wouldn't be much of a problem to add or patch
in a history mechanism.  UNIX-style environment variables would be more
difficult, i think, because they're a function of the operating system.  such
a modification would involve rewriting the F$fork call.
as for a path variable, that's possible, although it does involve the overhead
of searching the entire path when the shell starts up or when you do a rehash.
this may or may not be acceptable, depending on how fast your main i/o device
is.  for floppies i think it's not worth it.  it would be nice if you have a
hard disk or RAM disk, though.

Disclaimer:  my 6809 hacking days are over, so don't expect me to do any of
this.  i'm still wondering whether i'm better off now with Turing machines...
-- 
Matthew Belmonte
Internet:	belmonte@svax.cs.cornell.edu
BITNET:		belmonte@CRNLCS
*** The Knights of Batman ***
(Computer science 1, College 5, Johns Hopkins CTY Lancaster '87 session 1)