Lilypond in Debian Stretch

lilypond wasn't included in stretch, but has been backported

add

deb http://ftp.debian.org/debian stretch-backports main

to /etc/apt/sources.list, and then

sudo apt update
sudo apt-get -t stretch-backports install lilypond

To install a new version of Racket on an old version of Debian

Running Debian 8 which has Racket 2.1.

Trying to work through

http://io.livecode.ch/learn/gregr/icfp2017-artifact-auas7pp

for which there is a Racket Package

2.1 is not good enough, need Racket 2.6

Check out:

https://backports.debian.org/Instructions/

$ su

# echo "deb http://ftp.debian.org/debian jessie-backports main" >> /etc/apt/sources.list

# apt update

# apt-get -t jessie-backports install racket

Now have Racket 2.7, which is good enough.