SHell programmin

[samona]

Hi,

 

I was wondering if someone could explain what the following code means.

 

if test "x$output" = "x"

 

Also, why would you put "x$output"  why not just "$output"  ?

 

[corbin]

The only thing that I can think of is that it's checking if $output is empty....

 

Maybe someone that actually knows what's going on can help more though ;p.

[samona]

Yeah, i think you're right.  So if $output is empty then x$output would equal x.  But why not just say if $output="" or maybe that's not possible in shell programming?

[trq]

The only thing that I can think of is that it's checking if $output is empty....

 

It is indeed, in a very roundabout way. There a better methods built into bash.

 

if [ -z $output ] ; then
  echo '$output is empty'
fi

[corbin]

Weird....