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From: jas@drutx.UUCP (ShanklandJA)
Newsgroups: net.unix
Subject: Re: HELP! (What's wrong with this sh scr - (nf)
Message-ID: <211@drutx.UUCP>
Date: Tue, 24-Apr-84 14:54:31 EST
Article-I.D.: drutx.211
Posted: Tue Apr 24 14:54:31 1984
Date-Received: Thu, 26-Apr-84 01:29:02 EST
References: <3135@fortune.UUCP>
Organization: AT&T Information Systems Laboratories, Denver
Lines: 19


    > To guard against this, always (1) use double-quotes around
    > your read-in strings and (2) pad such strings with a leading
    > character to keep them from ever being null:

        > if [ "X$ANSWER" = Xyes -o "X$ANSWER" = Xye -o "X$ANSWER" = Xy ]

I've always wondered about this curious custom of prefixing strings with X
(or whatever) to keep them from being null.  Why?  The System V Bourne
shell finds null strings perfectly acceptable; of course, they have to be
quoted, because the empty string is not the same as no string at all.  In
any case, I find that:

if [ "$ANSWER" = yes -o "$ANSWER" = ye -o "$ANSWER" = y ]

works just fine, even when $ANSWER is null.  Those X's look ugly to me.
Am I missing something?

Jim Shankland
..!ihnp4!druxy!jas