Did you check these?;
http://answers.ros.org/question/195052/command-not-found-roscd-rosnode-etc/
http://answers.ros.org/question/66913/roscd-command-not-found-in-groovy-1204/
Also you can check your environment variables.
Originally posted by Akif with karma: 3561 on 2015-12-10
This answer was ACCEPTED on the original site
Post score: 0
Original comments
Comment by Reza1984 on 2015-12-10:
Yes I have checked all the possible solutions in the net but none of them worked.
Comment by Akif on 2015-12-10:
Can you check printenv | grep ROS
output?
Comment by Reza1984 on 2016-03-03:
Sorry for late reply. I have installed ROS again and it works now.
Comment by Akif on 2016-03-03:
Glad you solved it.