current dir from .command scripts

[Hacker Scot]

On Aug 4, 2007, at 7:04 AM, Andy Lee wrote:

> $0, $1, $2 etc. is replaced by the shell with the nth argument to  
> the current command.  The zeroth argument, $0, is the command name  
> itself, which is bash when you enter commands in your Terminal window.
>
> If you do "echo $0" at the shell, you get "-bash".  (I don't know  
> why it's that instead of "/bin/bash".)  So "dirname $0" expands to  
> "dirname -bash".  Putting backticks around "dirname $0" causes  
> "dirname -bash" to be evaluated by the shell.  The shell thinks you  
> are trying to pass a -b option to dirname, which it doesn't support.
>
> If you were to include "echo `dirname $0`" in a *script*, it would  
> succeed, because the "zeroth" argument to the script is the path to  
> the script file.

Interestingly, the

echo `dirname $0`

trick gives the full working path for .command scripts that are  
double-clicked, but just "." (current dir) for the same script run  
from the shell. My script is designed to be double clicked, so this  
largely solved it for  me, but just in case, I'll have to build in  
some logic to determine whether it's being double-clicked or run from  
the shell, using pwd to get the path if dirname $0 evaluates to "."

Funny business.

./s