Re: exec (or system())

Floor wrote:

> With a 'cat' command I read out the contents of the e-mail adresses of the
> subscribers and put it in one viewable textfile.
> I now run that job in a crontab job that runs every 15 minutes.
> It would be great if I can run that job at the start of the Perl script of
> the mailinglist software. I allready tried to put the system line in it, b
ut
> as I am a complete nono on Perl,

I don't know "nono"; I assume you mean "am a complete newbie when it comes t
o Perl".
That's OK, we all were at one time.

> it didn't run (it did, but didn't make an update to the online output file).[/colo
r]

Did your other script check for errors?  (In particular: "permission denied"
.)

I hope you're aware that when the web server runs your CGI script, it runs
as "nobody" (or some other unprivileged user-ID) and not as "floor".
That is, if the output file has the usual file permissions, so that it can
only be written to by a process logged in as you, then the file cannot
be written to by the CGI script when run by the web server.
 
>
> I think there might be allway a security issue on this, but in this case i
t
> will be the only alternative I am afraid.

Using
system "./my-script" == 0 or warn "Problem running ./my-script: $? ($!)";
or
my $results = `./my-script`; warn "Problem running ./my-script: $? ($!)" if 
$?;
has some of the same sort of security issues as
open my $fh,'>',$filename or warn "Cannot write to $filename: $!";
in regards to: Output files need to be writable by the web server process.

> I am not an experienced Perl users, but as with Cobol, you have to put the
se
> kins of commands in a certain part of the source code or else the command
> wouldn't be executed.

Perl does not have those sorts of silly restrictions.  Any executable statem
ent
that is not inside a subroutine definition is considered to be part of the
main program.  It will be executed if the flow of control reaches that far.

On another topic, I recommend you look into the comp.lang.perl.misc newsgrou
p;
it has a lot more traffic than the alt.perl newsgroup.
-Joe

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