Radiate - automated internet radio

For the past couple of months I've been working on an automated internet radio system based on Liquidsoap, with scripts written (so far) in bash.

Here is the github repo: https://github.com/jimsheldon/radiate

Documentation is almost non-existent at this point, the system is currently very rigid and probably not much good to anyone else as-is. My hope is to get it to the point where someone could easily grab the code and deploy their own station in a few simple steps.

Bash substring exclusive replacement

This is a neat little trick I figured out today. I needed to remove all characters from a variable that were not digits or spaces. I've done a lot of variable manipulation in bash, but nothing with more than one condition.

It turns out that you can negate with the ^ character, combined with the | "or" character to get this:

$ MYVAR="4322, #32"
$ echo ${MYVAR//[^[:digit:]|[:space:]]/}
4322 32

SSH chained port forwarding

I might be late to the party on this, but I just realized that you can chain forwarded ports in ssh!

For example:

ssh -L port1:<ip address>:hostport1 -L port2:<ip address>:hostport2 somewhere.com

I'll admit, I'm guilty of opening multiple ssh sessions to forward each port that I needed... Never again!

Convert Xen XP domU to KVM

Recently I needed to take a windows XP VM under Xen from my workstation and move it to my laptop running KVM.

The Xen VM uses an LVM block device. I was able to use qemu-img to convert the raw LVM block filesystem into the compressed qcow2 format:

qemu-img convert -c -f raw -O qcow2 /dev/vgxen/xp xp.qcow2

This took over an hour, since the filesystem is 100GB.

Back over on my laptop, importing the qcow2 image was a breeze. I simply launched "Virtual Machine Manager" and selected "importing existing disk image", and pointed to the image.

XP booted fine, but I did have to re-activate windows due to hardware "changes" that windows saw.

The qcow2 format is nice since it's compressed, but there is definitely a performance hit. I plan on experimenting with moving the VM to an external eSATA drive, on a raw block device, and see how much it helps performance.