I downloaded the latest version of Scala and saved it to /opt folder. Then I tried to add /opt/scala-2.11.2/bin to the PATH in order to have easier access to commands like scala and scalac. After executing the command :
export PATH=$PATH:/opt/scala-2.11.2/bin/
and then :
echo $PATH
I see the path in there. At that time I can also use the commands scala and scalac.
Then if I close the terminal and restart , the path /opt/scala-2.11.2/bin/ is not in echo $PATH anymore. And thus I can not execute the commands . What is my problem ?