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

> ...
> fi

I've never understood that one myself.  I've always put it down to
people who don't know about the -z operator or learned shell scripting
in an environment in which it was not available.


-- 
  Phil Stracchino, CDK#2     DoD#299792458     ICBM: 43.5607, -71.355
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         Renaissance Man, Unix ronin, Perl hacker, Free Stater
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