> > Because the space between $4 and $5 in {print $4 $5} is
> > a concatenation operator.
> >
>
> so what's the right way to avoid the concatenation operator?
Use a comma:
$ echo a b c | awk '{print $1 $2}'
ab
$ echo a b c | awk '{print $1, $2}'
a b
$
Kenn