hi all. recently i install rosmake and rviz and other related packages such

ros-desktop-full
python-rosmake
rviz

i think have unknown problem when i try to run rviz. first i run roscore then i run rviz. but i cant put any shape in this plane. i cant see target frame in global options and so on. even when i want to run rviz with rosrun rviz rviz i get this error:

/usr/bin/rosrun: line 56: rospack: command not found

i use ubuntu 16.04. and i'm very new to this word so i think i miss some packages. thanks