On Nov 8, 2011 1:01 PM, "Pandu Poluan" <pa...@poluan.info> wrote: > > > 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"] ) >
Uh... of course there should be a space between the second double-quote and the closing bracket. Rgds,
