F18, F19 webalizer problem?

[Adam Williamson]

On Fri, 2013-04-26 at 16:42 +0300, Cristian Sava wrote:
> On Fri, 2013-04-26 at 08:30 -0500, Chris Adams wrote:
> > Once upon a time, Jonathan Kamens <jik at kamens.us> said:
> > > This, however, is fine:
> > > 
> > > [ "$WEBALIZER_CRON" != yes ]
> > > 
> > > because the quotes ensure that the statement will be evaluated with an 
> > > expression to the left of the != even if the expression is just an empty 
> > > string.
> > > 
> > > This is fine too:
> > > 
> > > [ z$WEBALIZER_CRON != zyes ]
> > > 
> > > because if the variable is empty, the expression to the left will be "z" 
> > > rather than an empty string.
> > 
> > The reason some use a combination of quotes and a leading character is
> > for testing user-provided input.  It shouldn't matter in this case, but
> > it is just a little bit more defensive programming.
> > 
> > The problem if you are testing a user-provided variable is that they
> > could give input that starts with a dash, a close bracket, etc., and
> > that would screw up the test.  Putting a character at the start protects
> > against that.
> > 
> > Also, always quoting the variable is good programming practice; it could
> > have whitespace in it, in which case the non-quoted version would expand
> > to multiple tokens (and again break).
> > 
> > So, still today, the best defensive way is:
> > 
> >    [ "z$WEBALIZER_CRON" != zyes ]
> > 
> > -- 
> > Chris Adams <cmadams at hiwaay.net>
> > Systems and Network Administrator - HiWAAY Internet Services
> > I don't speak for anybody but myself - that's enough trouble.

> Good to know. Thank you very much,

I think we *all* learned something here today :)

(actually I finally figured out the reason for this independently, just
last month or so. Only took me thirteen years of Linux use...)
-- 
Adam Williamson
Fedora QA Community Monkey
IRC: adamw | Twitter: AdamW_Fedora | identi.ca: adamwfedora
http://www.happyassassin.net