Show version of operation system, kernel and distribution

[swedebugia]

In other GNU/Linux systems you have:
 cat /proc/version
 uname -a
 lsb_release -a

I would like to document the equivalents for GuixSD, are these:
 cat /proc/version
 uname -a
 guix --version

?

Even though i recently pulled guix from git it still shows:
~/src/guix$ guix --version
guix (GNU Guix) 0.9.0

should we change this for it to say "master" or "git pulled at hash 
xxxxxx" instead?