I am using ubuntu 15.10
ionic version 1.7.15.
I was trying to update my nodejs to laters version 6 and npm and after that when i run ionic server command i am getting error shown in 
the command i used to update
sudo npm cache clean -f
sudo npm install -g n
sudo n stable
how to to downgrade my nodejs
when i use whereis node command
node: /usr/local/bin/node /opt/node/bin/node
when i use whereis nodejs command
nodejs:
when i use whereis npm command
npm: /usr/local/bin/npm /opt/node/bin/npm
I think i have to use lower version of node but i dont know how to do is i have tried my cmd but no use
ENOSPCsuggests that your filesystem might be full.