On Wed, 03 Mar 2010, Brian Debelius might have said:

> 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
> ...
> fi

Historically the -z test is not available on many systems, hence the
"x$var" format. Also, put a space between ] and ; like

if [ "x$var" = "x" ] ; then
        ...
fi

Mike

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