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, ...)

How do I "execute" Ruby templates from command line?

Answer 1

You should have everything you need in your ruby/bin directory. On my (WinXP, Ruby 1.8.6) system, I have ruby/bin/erb.bat

erb.bat [switches] [inputfile]
  -x               print ruby script
  -n               print ruby script with line number
  -v               enable verbose mode
  -d               set $DEBUG to true
  -r [library]     load a library
  -K [kcode]       specify KANJI code-set
  -S [safe_level]  set $SAFE (0..4)
  -T [trim_mode]   specify trim_mode (0..2, -)
  -P               ignore lines which start with "%"

so erb your_erb_file.erb should write the result to STDOUT.

(EDIT: windows has erb.bat and just plain "erb". The .bat file is just a wrapper for erb, which I guess should make the same command work pretty much the same on any OS)

See the prag prog book discussion (starts about half-way down the page).

Note also that Jack Herrington wrote a whole book about code generation that uses Ruby/ERB.