Rafael Fernandez wrote: > Thanks, I wasn't aware that positional parameters greater than nine have to > be enclosed in brackets.
No prob. The manpage says When a positional parameter consisting of more than a single digit is expanded, it must be enclosed in braces (see EXPANSION below). If you have an idea for making this clearer (maybe somewhere in the info documentation) I imagine it would be welcome. For the future, the sh specification at http://www.unix.org/2008edition/ (free registration required) is also very useful for tracking down how a shell might understand a script.