Distribution

Usage

lsb_release -a

Three different methods:

cat /proc/version
cat /etc/issue
dmesg | head

Debian

Debian 7.0 (wheezy)
Debian 6.0 (squeeze)
Debian GNU/Linux 5.0 (lenny)
Debian GNU/Linux 4.0 (etch)
cat /etc/debian_version