Henning: || Scripsit zweije@xs4all.nl (Vincent Zweije) || > I would write [ "${1:+x}" ], or rather even [ "${1+x}" ], distinguishing || > empty and undefined. || || Wouldn't work. Most shells (and /bin/['s) are fine with empty || arguments, but some get confused if the first character of the || argument is a dash, such that it can be interpreted as an option. || Hence the 'x' in front. No leading dash occurs in these two examples. The substitutions yield either "x" or "", depending on $1. But we're digressing. The compatibility argument that was mentioned explains why avoiding -z would be better. I don't know if there are compatibility problems when using ${var+value}. Ciao. Vincent.
Attachment:
signature.asc
Description: Digital signature