On Nov 8, 2011 9:02 AM, "Claudio Roberto França Pereira" <spide...@gmail.com> wrote: > > What about [[? I've seen scripts using [[ instead of only one [. Whats the point/difference?
AFAIK [[ was originally a bash-specific built-in command that provides more functionality than /bin/[, but can still use /bin/['s convoluted syntax. The two converged quickly, though. IIRC [ is now also a bash built-in, which still maintains compatibility with /bin/[ An example: [ $VAR ] will produce an error if VAR is empty or unset, but [[ $VAR ]] won't. (for the former, you have to put double quotes around, e.g., [ "$VAR"] ) Rgds,
