Why isn't this code working? (exec)

[TrickyPhillips]

if (isset ($_POST['submit']))
  {
     // Post to DB.
     mysql_connect(localhost,$dbuser,$dbpass);
     mysql_select_db($dbname) or die("Unable to select DB!");
     $query = "INSERT INTO users VALUES('','$name','$date')";
     mysql_query($query);
     mysql_close;

 // Generate SQL Dump.
 $database     = "vbulletin";
 $backupdir    = "[removed for security :)]";
 $mysqldumpcmd = "/usr/bin/mysqldump";
 $userpassword = " --user=$dbuser --password=$dbpass";
 $dumpoptions  = " --quick --add-drop-table --add-locks --extended-insert --lock-tables";
 $gzip         = "/bin/gzip";
 $today        = "";
 $do           = "$mysqldumpcmd $userpassword $dumpoptions $database > $backupdir/$database.sql";
 echo "Dumping MySQL Databases. Please Wait....<br>";
 exec($do);
 echo "Removing Old Gzipped Database. Please Wait....<br>";
 $do           = "rm -f ${backupdir}/${database}.sql.gz";
 exec($do);
 echo "Compressing Dumped Files. Please Wait....<br>";
 $do           = "$gzip $backupdir/$database.sql";
 exec($do);
  }
?>

Am I using exec incorrectly?

[nemonoman]

You are using the command correctly, but debugging will be tough.

Best to echo the content of the command that isn't running, and manually paste into your terminal.

If you are using shared server space, be sure that the exec command is available for your use. Some admins don't allow it.

[TrickyPhillips]

I can't get exec to work, even with a simple mkdir. I've tried on my VPS, and my own Linux machine, but am unable to get it working for this purpose.

The only thing I could get exec to do, was to display the output of programs. Is there another command that I can try? 🙂