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From: jdpeek@rodan.acs.syr.edu (Jerry Peek)
Newsgroups: comp.unix.questions
Subject: ENV file in ksh: is this smart? legal?
Keywords: ksh, ENV
Message-ID: <716@rodan.acs.syr.edu>
Date: 30 Aug 89 17:10:22 GMT
Sender: jdpeek@rodan.acs.syr.edu
Reply-To: jdpeek@rodan.acs.syr.edu (Jerry Peek)
Organization: Syracuse University, Syracuse, NY
Lines: 43

Two questions about things in ksh that don't seem to be answered in TFM.
We've got ksh Version 06/03/86a on a Gould NP1, UTX/32 (BSD-like).
[This is a re-post of a message that didn't get out before, I think.
Our news posting was set up wrong.  Sorry if you've seen this.]

#1.  I want it my ENV file to act like the ".cshrc" file in csh --
to be read anytime a new, interactive shell starts.
So, I have my ENV variable set this way in .profile:
	ENV='$HOME/.kshrc'; export ENV
The filename is in single-quotes.  That way, when I run the 'su'
command to start a shell on another account, the ksh on *that* account
will read the .kshrc file for *that* account's $HOME.  (If I'd used
double-quotes, the *same* .kshrc file would be read for *all* accounts.)
So now, each time I start a shell, it reads that account's $HOME/.kshrc.

Anybody see problems, or know another way to make this work?

#2.  The next problem I have with ENV files -- if their name is stored
in the environment (export ENV) -- is that Korn shell script files
(shell programs) read them too.  I have some stuff in my ENV file that
screws up shell scripts.

Here's how I fixed the problem.  I put this at the start of my ENV file:
	case "$-" in
	*i*) ;;	# IF SHELL IS INTERACTIVE, READ THIS FILE
	*) return ;; # ELSE, EXIT AND DON'T READ IT
	esac
It works.  For non-interactive shells, the ENV file isn't read --
and the rest of the shell program runs just fine, like I want.

The problem is, TFM doesn't seem to say whether that's legal.  It says:
	- If return is invoked while not in a function or a script,
	  then it is the same as an exit .
	- exit n  Causes the shell to exit with the exit status specified by n.
The first one says that return inside a script is not the same as exit,
but it doesn't say *how* it's different.  (Is an 'ENV' file a "script?")
Anyhow, am I doing anything that I'll regret? :-)

Thanks...

--Jerry Peek; Syracuse University Academic Computing Services; Syracuse, NY
  jdpeek@rodan.acs.syr.edu///jdpeek@sunris.bitnet///GEnie: J.PEEK1
  +1 315 443-3995