I have installed ROS using
sudo apt-get install ros-desktop-full
all tutorial on the net says configure enviroment setup using command
source /opt/ros/<dist>/setup.bash
I don't find any folder with the name ros in my /opt/
I can only see only following folders after executing the command
$ ls /opt/
atom google SQLiteStudio zoom
You used the wrong apt
command. You should use sudo apt install ros-<distro>-desktop-full
. Assuming you're on Ubuntu20.04 and wanting to run ROS Noetic the command is sudo apt install ros-noetic-desktop-full
.