What do I do to fix 'heroku: command not found'?

Question

I'm having a problem when I try to use "heroku create" in my ruby project, every time I do this show up this on the shell:

command I type:

/demo_app$ heroku create

Result I receive:

Setting up node-v4.2.1... ▸    Get https://cli-assets.heroku.com/node/v4.2.1/node-v4.2.1-linux-x64.tar.gz: dial tcp: lookup cli-assets.heroku.com on 127.0.1.1:53: cannot unmarshal DNS message
 !    error getting commands pid 11838 exit 1

I have all last version you can imagine:
ruby 2.2.3
rails 4.2.4
nodejs v4.2.1

And I have noticed something when I run 'which heroku' command. I have this in my Ubuntu system:
/usr/local/heroku/bin/heroku

Is it possible that folder may conflicting with heroku Cli?

I need your help, please! I searched for the solution but I didn't find.

Answer 1

after install toolbelt or heroku gem, you must be login as a root and please try

sudo su
heroku login

this problem maybe cause different Invalid cross-device link error with boost filesystem

Answer 2

After so many angry I decided not to use heroku anymore, I put my application in openshift and it is solved my problem.

Answer 3

I found the solution for this issue, I executed this command here in order remove heroku from computer:
rm -rf ~/.heroku
sudo rm -rf /usr/local/heroku /usr/bin/heroku

After that I installed Heroku Cli, but I have another issue, the heroku commands is not working.

Now my issue is that:
heroku: command not found