How do I execute ruby template files (ERB) without a web server from command line?

Question

I need ERB (Ruby\'s templating system) for templating of non-HTML files.
(Instead, I want to use it for source files such as .java, .cs, ...)

Answer 1

Found this question while trying to test my Puppet templates.

Ended with this solution:

1. Along your foo.erb create a file foo.vars.erb

2. Put all your template variables into that new file, e.g.:

   <% @my_param="foo bar" %>
   <% @another_param=123 %>
   

   or (equivalent):

   <%
   @my_param="foo bar"
   @another_param=123
   %>
   

3. On command line run this:

   cat foo.vars.erb foo.erb | erb
   

Your fully rendered template should now be printed to std-out. From there you check the output by hand, or you can take diff (or other tools) to compare it to a pre-rendered output.