Ruby 1.9 If I have a shebang pointing to ruby, why doesn't the system see it?

Question

I'm using Ubuntu. I'm trying to run a ruby file todo.rb I added this shebang as the very first line of the file

#!/usr/bin/env ruby

I go to the directory where the rb file is located and then run todo.rb and get error todo.rb: command not found.

So I went directly to the /usr/bin directory. I found the env command and ran it. The output of the env command displays ruby paths and ruby data:

MY_RUBY_HOME=/home/tallercreativo/.rvm/rubies/ruby-1.9.2-p290
PATH=/home/tallercreativo/.rvm/gems/ruby-1.9.2-p290/bin:/home/tallercreativo/.rvm/gems/ruby-1.9.2-p290@global/bin:/home/tallercreativo/.rvm/rubies/ruby-1.9.2-p290/bin:/home/tallercreativo/.rvm/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
GEM_PATH=/home/tallercreativo/.rvm/gems/ruby-1.9.2-p290:/home/tallercreativo/.rvm/gems/ruby-1.9.2-p290@global
RUBY_VERSION=ruby-1.9.2-p290

So since, I couldn't make it work, I changed the shebang to point to ruby directly:

#!/home/tallercreativo/.rvm/rubies/ruby-1.9.2-p290/bin/ruby

and I get same command not found error. What's wrong?

Answer 1

You need to first make your script executable:

chmod +x todo.rb

then you need to run it like so:

./todo.rb

You cannot run it by just saying todo.rb, unless you place it in your PATH, in which case you can do so from anywhere.

Answer 2

You're missing the ruby at the end of your env command. Did you mean:

#!/usr/bin/env ruby

You need to tell env what executable you're looking for.

(Question Updated)

Are you executing your code like this? todo.rb ? You either need to provide the full path to your script (/home/you/project/todo.rb) or a relative path (./todo.rb) unless that directory is inside your $PATH.