More info:
$ whereis lsb_release lsb_release: /usr/bin/lsb_release /usr/bin/X11/lsb_release /usr/share/man/man1/lsb_release.1.gz
$ lsb_release -d Description: Ubuntu 12.04.2 LTS
$ lsb_release -ds Ubuntu 12.04.2 LTS
More info:
$ whereis lsb_release lsb_release /usr/bin/ X11/lsb_ release /usr/share/ man/man1/ lsb_release. 1.gz
lsb_release: /usr/bin/
$ lsb_release -d
Description: Ubuntu 12.04.2 LTS
$ lsb_release -ds
Ubuntu 12.04.2 LTS