Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!ncar!oddjob!gargoyle!att!pacbell!well!shf
From: shf@well.UUCP (Stuart H. Ferguson)
Newsgroups: comp.sys.amiga
Subject: Re: Enviroment (was Re: Yea, but can an Amiga Shell do this....)
Message-ID: <6890@well.UUCP>
Date: 22 Aug 88 19:49:46 GMT
References: <8808220455.AA27577@cory.Berkeley.EDU>
Reply-To: shf@well.UUCP (Stuart H. Ferguson)
Organization: The Blue Planet
Lines: 49


From: dillon@CORY.BERKELEY.EDU (Matt Dillon)

| :How does this allow a child to have an environment different from its
| :parent?  Specifically
 	[specific example tree deleted]

|         It doesn't, [...]

There is a way to do it, which is to have a subdirectory for each
process in the tree.  When a child process looks for a given context 
variable, it looks in its own subdirectory first, then, if it doesn't 
find the given variable, it looks in its parent's directory and so on.  
This gives inheritance behavior using a file-structured device and 
without duplication of data.

There are a couple of added advantages to this method over the SetEnv 
interface.  You can modify the context variables for a different process 
by changing files in its subdirectory.  Also, subdirectories could stick 
around after the process exits so that when the same process starts up 
again, it goes back to having its context set up the way it was last 
time.

| ... in
| fact, none of the environment is in memory if you assign ENV: to your floppy 
| or hard disk.

Having "environment" variables on recoverable media such as floppy or 
hard-disk or even rrd is really great since you don't need to do a long 
series of SetEnv commands in your startup, you can just do one Assign 
and your environment is the way you want it.  Also, every change to 
your environment does not require editing your startup sequence; you 
just change the ENV: directory and the change is made permanently.

It might be nice, however, to have an environment search path, so that 
permanent environment vars could be set up on hard disk, and temporary 
changes for the current shell could live on RAM:.  Just an idea.

|  Neither are there limitations to the environment size...
| Individual environment variables can theoretically hold entire file's worth
| of data.  The only plausable assumption one can really make is that 
| environment variables contain ASCII (can we even do that?).

Why impose that constraint?  IFF would be nice for ENV: files such as
Workbench-Backdrop and Guru-Sound.  :-)

|                                 -Matt 
-- 
		Stuart Ferguson		(shf@well.UUCP)
		Action by HAVOC		(shf@Solar.Stanford.EDU)