Tiptop Software Company

I’ve ripped a bunch of my CDs onto my computer over the years and many of them ore in the open OGG format which doesn’t work with my iPod or Treo. I wrote a simple little script to convert the OGG files to MP3 for my phone. Since Real Player on my phone only seems to support a flat directory structure, I created the file names out of artist and song name. I just mount up the SD card, change directory to it and run the script passing the songs I want to copy on the command like. Using wild cards makes it easy. For example:

cd /media/sdcard ;
ogg2mp3 /home/terry/jukebox/Yeah_Yeah_Yeahs/Show_Your_Bones/*

The script looks like this…

USAGE=false
if [ ! -f "$1" ]
then
echo "Usage $0 sourceFiles ..."
exit 1
fi TMPFILE=/tmp/tmp$$.wav
while [ $# -gt 0 ]
do
ogg123 -d wav -f $TMPFILE "$1"
DIRNAME=`dirname "$1"`
ALBUM=`basename $DIRNAME`
TMP=`dirname $DIRNAME`
ARTIST=`basename $TMP`
MP3FILE=`basename "$1" | sed -e 's/.ogg/.mp3/' | sed -e     's/^[0-9][0-9] - //'`
OUTFILE="${ARTIST}_${MP3FILE}"
echo "-------------$OUTFILE"
lame $TMPFILE "$OUTFILE"
shift
done
rm -f $TMPFILE

I’m trying to generate some generic SSL certificate code for Postfix and other products. This is customized for Postfix, but it is easy to change the output files. I’ve put this together to be a cut and paste, just set the environment variables.

keyfile=/etc/ssl/private/smtpd.key
certfile=/etc/ssl/certs/smtpd.crt
pemfile= /etc/ssl/certs/cacert.pem
pass=superSecret
openssl genrsa -des3 -rand /etc/hosts -passout "pass:$pass" -out $keyfile 1024
chmod 600 $keyfile
openssl req -new -passin "pass:$pass" -passout "pass:$pass" -key $keyfile -out /tmp/.server.csr
openssl x509 -req -days 3650 -passin "pass:$pass" -passout "pass:$pass" -in /tmp/.server.csr -signkey $keyfile -out $certfile
openssl rsa -passin "pass:$pass" -in $keyfile -out /tmp/.server.unencrypted
mv -f /tmp/.key.unencrypted $keyfile
openssl req -new -x509 -extensions v3_ca -keyout cakey.pem -out $pemfile -days 3650

If you run a server on the Internet and you do any type of security logging, you know people are constantly trying to find vulnerabilities to your site through ssh. You’ll get pages and pages of PAM authentication errors. Avoiding this is not difficult, just change the port your sshd listens on. Modify the Port parameter in /etc/ssh/sshd_conf and run /etc/init.d/ssh restart. When you log into the system, specify the port on the command line with the -p option.

ssh -p 404 www.tiptopsoftwarecompany.com

Remember getty? Remember kermit? If you already put a fork in these utilities, think again. They are still useful today if you want to log into your Linux box over the serial port.

The first step is to make sure the serial port is enabled in the BIOS. I’ll often disable the serial port because it is not in use. Once it is enabled, add an entry in the /etc/inittab to start the getty process on your serial port. On Ubuntu, you just need to uncomment out the following:

T0:12345:respawn:/sbin/getty -L ttyS0 9600 vt100

In the event that the machine you are going to be logging in from is another Linux box, kermit makes a good choice to do the logging in. The rate can probably be set higher than 9600, but it works. To get back to the kermit prompt, type the escape character is ctrl-\ followed by a C. This will get you back to the kermit prompt. You can type connect to return.

-bash-3.00$ kermit -b 9600 -l /dev/ttyb
C-Kermit 8.0.211, 10 Apr 2004, for NetBSD 1.6
Copyright (C) 1985, 2004,
Trustees of Columbia University in the City of New York.
Type ? or HELP for help.
(/u1/terry/) C-Kermit>set carrier-watch off
(/u1/terry/) C-Kermit>connect
Connecting to /dev/ttyb, speed 9600
Escape character: Ctrl- (ASCII 28, FS): enabled
Type the escape character followed by C to get back,
or followed by ? to see other options.
----------------------------------------------------

Ubuntu 6.06.1 LTS m715.tiptopsoftwarecompany.com ttyS0

m715.tiptopsoftwarecompany.com login:

A useful tcpdump command is the following:

tcpdump port 554 -xX -s 0 -l | tee tcpdump.out

When you want to see the specific messages of a protocol, in this case RTSP running on default port 554, this command shows you the output in “human” readable form.

The -s 0 shows the whole packet. The -x also shows the packet in hex.