a trick with perl

[Chris Fortune]

After some major quality time with my manuals, I discovered how to create a
RAM device, create temporary files in it, and feed them to bogofilter (and
several other filters via the command line).  If you are the owner of a
disc-bound system with plenty of RAM, this trick could be very useful.  Here
is the code to create a RAM disc (as root):

dd if=/dev/zero of=/dev/ram0 count=1440 bs=1024
mke2fs /dev/ram0
mkdir /home/username/mnt
mount /dev/ram0 /home/username/mnt
chown username /home/username/mnt   # so that 'username's scripts can read
and write to it
ls -al /home/username/mnt

What I found most surprising on my system was that the RAM device was *not*
much faster than simply creating a file on disc.

# ave. time to open, print 4kb data, close and unlink a file (1000 trials)
# using disc filesystem: 0.0000653883333333333 secs.
# using RAM device:   0.0000510116666666673 secs

I have dual scsi raid, which is apparantly pretty fast. The RAM device is
only about 22% faster, but I suppose it makes a difference as the months go
by, so I may as well use it, now that it's set up.:

        # create temporary file
        $temp_file = "/home/username/mnt/" . rand(100) . "\.tmp";
        print "$temp_file\n" if $DEBUG;
        open TEMP, ">$temp_file" or die $!;
        print TEMP $email_contents;
        close TEMP;

        # BogoFilter
        $bf = `bogofilter -T < $temp_file`;  # ahhh, so easy.  No messy
pipes
        print "BogoFilter response:  $bf\n";

        # Vipul's Razor
        ... etc...
        # ClamAV
        ... etc...
        # Pyzor
        ... etc...