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
------------------------------------------------------------------------------
Download Intel® Parallel Studio Eval
Try the new software tools for yourself. Speed compiling, find bugs
proactively, and fine-tune applications for parallel performance.
See why Intel Parallel Studio got high marks during beta.
http://p.sf.net/sfu/intel-sw-dev
_______________________________________________
Bacula-users mailing list
Bacula-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/bacula-users
