Is there a shell command to get ros distro?

edit

A quick Google search gives me #q33769. The more recent of the two answers there show that if you want to see which distro is in use (Indigo and later), run

rosversion -d

otherwise run

rosversion ros

to see the version for pre-Indigo (for me this command returns <unversioned>, I'm using Indigo).

Edit:

as @gvdhoorn pointed out in the comments

Additionally, after sourceing the right setup.bash, the ROS_DISTRO environment variable should be set.

Which means that you can get the ROS distribution with

echo $ROS_DISTRO

as well