bug#79901: Inconsistency between '-n STRING' and 'STRING' in TEST

tag 79901 notabug
close 79901
stop

details below...

On 27/11/2025 12:33, Carlos Maiolino via GNU coreutils Bug Reports wrote:
> Hello,
> 
> I'm not sure if the behavior below is expected or perhaps a bug?
> I'm using GNU coreutils 9.6
> 
> According to the TEST(1) manpage:
> 
>         -n STRING
>                the length of STRING is nonzero
> 
>         STRING equivalent to -n STRING
> 
> 
> However, the small script below will produce inconsistent results, where
> only the first if conditional will evaluate to True:
> 
> #!/bin/bash
> 
> B=" "
> 
> if [ -n $B ]; then
>          echo "passed 1"
> fi
> 
> if [ $B ]; then
>          echo "passed 2"
> fi
> 
> 
> However it seems to me the variable expansion plays a role here, I'm not
> sure if the variable expansion was supposed to differ between "$B" and
> "-n $B" too, so perhaps it's a bash thing not a "test" thing?

You need to quote the variable expansion to maintain spaces,
otherwise `test -n $B` is equivalent to `test '-n'` which is true.

You want: [ -n "$B" ] && [ "$B" ] && echo both passed

cheers,
Padraig.