peschkaj has asked for the wisdom of the Perl Monks concerning the following question:

I wrote a piece of cam-like software today out of shear laziness and nothing to do at work. I have found a program that works astonishingly well (gqcam) on my linux box. The only problem being that it doesn't auto upload. So, I took it upon myself to write some code for it: 
#!/usr/bin/perl -w

use Net::FTP;

my $hostname;
my $username;
my $password;
my $boink;
my $directory;
my $filename;
my $ftp;
my $sleeptime;

$boink = 0;

`gqcam &`;

while ($boink == 0) {
    $ftp = Net::FTP->new($hostname) or die "can't connect: $@\n";
    $ftp->login($username,$password) or die "can't login: $@\n";
    $ftp->cwd($directory) or die "can't cwd to $directory\n";
    $ftp->type(binary) or die "cannot change type to binary\n";
    $ftp->put($filename) or die "cannot put $filename\n";
    $ftp->close;
    sleep($sleeptime);
}

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Although this is nothing revolutionary, I thought that I might as well post it because it runs under -w, as far as I am aware. I attempted to launch gqcam from the program with: `gqcam &` but that generated error after error for the cam program. How could I get perl to call gqcam and not spew forth masses of errors to gqcam?

Replies are listed 'Best First'.
Re: Slew or error messages
by runrig (Abbot) on Aug 08, 2001 at 00:20 UTC
    You're using alot of uninitialized variables there. And one bareword. I'd use strict for good measure. I don't know what gqcam does, are you trying to process the output of it, or interact with it? If the former, save the output to a variable:
    my @array = `gqcam...`;

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    If the latter, then use Expect. Also '$boink' never changes; did you want an infinite loop?

    And when putting things between code tags, you don't have to escape '&' as '&'. I'm assuming that you don't really have '&' there.

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[d/l]

      I intentionally left the code general so that people could try it out themselves. the & came in from the HTML thingamajig, somehow.

      gqcam is a webcam program. I merely want to launch it in the background and have it update the cam every $howevermany seconds. It saves a file that is uploaded to the ftp server by this snippet of code.

      As for $boink, I would like for the loop to be infinite until i close that terminal window or kill the process.

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[d/l]
        You might have some contention issues if you start your upload while gqcam is rewriting the file. You might want to rename the file first, wait a bit, then upload the renamed file. And go ahead and use system to start gqcam: system('gqcam &') and die "Error starting gqcam";

        For an infinite loop, all you need is a bare block:

        LOOP: {
 #do stuff
 redo LOOP;
}

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        What sort of errors does gqcam 'spew'?? Are they significant, or can you just redirect them to /dev/null and ignore them?

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