(Groovy | 12.04 | armv7l) bash: rosrun: command not found

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I ran the following commands:

$ roscore
$ rosrun turtlesim turtlesim_node

and obtained the following error:

bash: rosrun: command not found

My environment reads:

root@localhost:~# export | grep ROS
declare -x ROS_DISTRO="groovy"
declare -x ROS_ETC_DIR="/opt/ros/groovy/etc/ros"
declare -x ROS_MASTER_URI="http://localhost:11311"
declare -x ROS_PACKAGE_PATH="/home/ubuntu/ros_ws:/opt/ros/groovy/share:/opt/ros/groovy/stacks"
declare -x ROS_ROOT="/opt/ros/groovy/share/ros"

And was not able to find the rosrun file at /opt/ros/groovy/bin

Any suggestions?