bash null conditional

[Mamoru Tasaka]

Craig White wrote, at 03/31/2009 03:27 AM +9:00:
> I'm in my bash book and looking on web but can't seem to resolve this
> simple problem.
> 
> $ if [ -n "grep A121 myfile.csv" ]; then echo "null"; fi
> null
> 
> $ if [ -n "grep A125 myfile.csv" ]; then echo "null"; fi
> null
> 
> A125 definitely is null when I just run the grep command in the quotes
> but A121 definitely is not null.
> 
> What am I missing on the if/null operator here?
> 
> Craig

Maybe what you want to is:
$ if ! grep -q "A125" myfile.csv ; then echo "null" ; fi
?