Re: How to run Perl script at Mac OS (Darwin) Release?

On Mar 9, 2008, at 11:12 AM, Doug McNutt wrote:
> Hashing of tools by shells has not been mentioned. It may not be  
> part of the problem but on invocation many, if not all, shells  
> examine the $PATH variable and make a table of executables that it  
> finds. The table is then converted to a hashed lookup array in  
> order to improve speed of response. (That probably makes little  
> sense today but it was started during the days of mag tape.)
>
> So if you create a perl script, place it somewhere in $PATH, and  
> set its execute permission a running shell will not find it. A full  
> path, perhaps starting with the current directory " . " always works.
>
> In tcsh the command to rework the hash of tools is "rehash".  
> Restarting the shell with a new Terminal.app window will do pretty  
> much the same thing.

It's not likely that Gary is having problems with his shell creating  
a hash table of executables on startup; he's using bash (the default  
in OS X these days), and bash doesn't do that:

>  test1.pl
>  -bash: test1.pl: command not found


If he had created test1.pl in a directory in his path (say, /Users/ 
gary/bin) but the executable bit wasn't set, he'd have gotten the error

-bash: /Users/gary/bin/test1.pl: Permission denied

even if the file was created after his bash shell started.  If he  
then had the executable bit set properly (chmod +x test1.pl) and  
didn't have a perl installed at /usr/local/ActivePerl-5.10/bin/perl,  
he'd have gotten the error

-bash: /Users/gary/bin/test1.pl: /usr/local/ActivePerl-5.10/bin/perl:  
bad interpreter: No such file or directory

Of course, maybe he's eschewing the default perl on OS X because he  
wants to use the 5.10 for some reason and he downloaded ActiveState's  
build for OS X; if that's the case, then that's probably the shebang  
line he wants.

Anyway, I'll shut up now, since people have just about beat this  
subject to death.  ;)

Here's hoping Gary's happily programming perl on his Mac now...

-packy

--
Packy Anderson                                               
[email protected]

If I had a boat, I'd go out on the ocean;
And if I had a pony, I'd ride him on my boat.
We could both together go out on the ocean--
Me upon my pony on my boat.