shell - Reliable way of finding out debian release name -

I have a script that needs to know what is the release name of the Debian system (Example: Dependable, CID, Volume e.t.c) ). I know that if I'm searching for / etc / debian_version on a Debian based system, I can find:

cat / etc / debian_version

Route @ 07156660e2cd: / # cat /

cat / etc / issue

etc. / debian_version 7.8 Root @ 07156660e2cd: / # cat / etc / issue
Debian GNU / Linux 7 \ n \ l

Production of Ubuntu:

Root @ A81e3f32b147: / # cat / etc / issue Ubuntu 14.04.2 lts \ n \ l

root @ a81e3f32b147: / # cat / etc / debian_version jessie / sid `` `

How can I codename Ubuntu (in this case 'Trustee') Do i say I do not want to please keep a dictionary of the release versions of the name, is there any way in the system to find this information?

Thank you!

Use lsb_release :

  Lsb_release -c