Re: [Sheflug] Running programs on file creation

["Graham Cox" <nospam [at] shef.ac.uk>]

I honestly don't know why that didn't occur to me earlier - Especially since
I'm teaching myself Perl at the moment :)
Oh - And the better way of doing the filter for . and . would be to filter
out all files begin with a . with a simple grep on the readdir, such as
@dir=grep(!/^\./, readdir(DIRECTORY));

Thankee for the suggestion anyway :)
--
Graham

An' Ye harm none,
do as Ye will.

----- Original Message -----
From: David Morris <nospam [at] allvac.co.uk>
To: <shef-lug [at] list.sheflug.org.uk>
Sent: Tuesday, August 28, 2001 6:18 PM
Subject: RE: [Sheflug] Running programs on file creation


>
> >
> > I've looked at it, and it isn't quite what I want. The
> > problem is that we've
> > only got one phone line, and my modem is quite stubborn about
> > such things as
> > detecting dial tones(It dials if someone's using the phone :( ). Also,
> > because of some of the programs that are run on the network(e.g. MSN
> > Messenger) it's going to be trying to connect to the net the
> > whole time(If
> > I've read things correctly that is :)
> > --
>
> This may sound stoopid (!), but how about a simple PERL script (or
similar)
> which polls your /var/lock/connect directory, but more frequently than
cron
> would? How about this as a starter?
>
> #!/usr/bin/perl -w
>
> while (1) {
>         sleep(5);
>
>         opendir DIRECTORY,"locks/";
>
>         @dir = readdir DIRECTORY;
>         foreach $dir ( [at] dir) {
>                 if (($dir ne ".") and ($dir ne "..")) {
>                         print "found file $dir so execute a program and
> restart\n";
>                         system("ps");
>                         last;
>                 }
>         }
>         closedir DIRECTORY;
>
> }
>
> Ok, I'm not the world's greatest PERL hacker. Someone will probably show
you
> a better way of testing for "." and ".." using pattern matching, but it
> works...
>
> The 'system("ps")' could be whatever you need to do to connect. Just make
> sure you remove the thing that caused the script to fire off a connection
in
> the first place otherwise 5 seconds later, it will reconnect again!
>
> Having just re-read your original email, this would work with a few extra
> tweaks. What you'd get with this approach that a simple cron job won't
give
> you is you have an opportunity to maintain the state of the program
between
> polls. That means you can remember that you're connected and that when the
> file disappears, you have to drop the connection.
>
> system() will suspend your script whilst the other program runs. I can't,
> off the top, find a way of running the second program concurrently. It's
> probably something to do with fork, but it's not something I've ever done
> before.
>
>
> Anyone else help?
>
>
> --
> David Morris
> work: david [at] allvac.co.uk
> home: david [at] brassedoff.net
> http://www.davidm.demon.co.uk
>
> ___________________________________________________________________
>
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>
>   GNU the choice of a complete generation.

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