* Martin Simmons schrieb am 04.03.10 um 11:40 Uhr:
> >>>>> On Thu, 4 Mar 2010 03:41:36 +0100, Marc Schiffbauer said:
> > 
> > * Phil Stracchino schrieb am 03.03.10 um 20:18 Uhr:
> > > On 03/03/10 14:05, Brian Debelius wrote:
> > > > Hi,
> > > > 
> > > >    Looking at Bacula scripts and other scripts, I see a test for an 
> > > > empty string performed by adding an 'x' before the variable, and then 
> > > > comparing this to another string that is just an 'x'.
> > > > 
> > > >    The shell test function has a -z string test that returns true if 
> > > > the 
> > > > string is empty.
> > > > 
> > > > It appears to me that more people use the 'x' comparison.  Is there a 
> > > > technical reason why one would be preferable to the other?
> > > > 
> > > >     Why would you do this:
> > > > 
> > > > if [ "x$var" = "x" ]; then
> > > > ...
> > > > fi
> > > > 
> > > >    Instead of this:
> > > > 
> > > > if [ -z $var ]; then
> > > 
> > > more properly:  if [ -z "$var" ]; then
> > 
> > 
> > Why not use 
> > 
> >   if [ "$var" = "" ]; then
> > 
> > if -z may not be available?
> 
> Because $var might be set to something like ! which would cause a syntax
> error.

Thx Martin, I did not know this. Is it only "!" because of some job
control stuff or everything that is not [:alnum:]?

-Marc
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