Path: utzoo!mnetor!uunet!husc6!bbn!uwmcsd1!ig!agate!ucbvax!HPLABS.HP.COM!hpsemc!bd
From: hpsemc!bd@HPLABS.HP.COM (bob desinger)
Newsgroups: comp.mail.mh
Subject: Re: Here's a way to expire old messages
Message-ID: <8802102006.AA05618@hpsemc.HP.COM>
Date: 10 Feb 88 20:06:54 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 47

(Greg Fowler pointed out that my message got rather severely truncated
along the way.  I think my original reply may have been truncated on
my machine; we ran out of filespace in /usr/spool one night, around
the time I sent this message.  But on with the show.)  Jerry Peek's
original comment went something like this:

> But "set -v" *does* show redirection... at least on our BSD-like
> Bourne shell.

My reply went on for a few screens showing the differences between
"set -x" and "set -v".  Here's the condensed version.

Our Bourne shell on System V (HP-UX) does exactly what Jerry's does,
so -v is the right flag to use here.  Use -x when you're debugging and
you want to see which lines are actually being executed.  Use -v when
you'd rather see the whole script, including redirection.  The -x flag
prints each line as it executes, omits lines that aren't executed
because a condition is false, and never mentions any redirection.
The -v flag prints the whole script as it's being parsed, including
lines that won't be executed, and shows redirection.

To be more concrete, the script:

	if true
	then	echo It was true on `date` >>results
	else	echo It was false, yow!    >>results
	fi

prints when executed with `sh -x':

	+ true 
	+ date 
	+ echo It was true on Wed Feb 10 11:58:48 PST 1988 

Notice no redirection, but trace lines showing which lines
were executed (the file "results" contains what you'd expect).
Using `sh -v' produces:

	if true
	then	echo It was true on `date` >>results
	else	echo It was false, yow!    >>results
	fi

This is probably closer to the output that Dave would like to see
in his notification, so I agree with Jerry:  use -v instead of -x.

-- bd