[me@mypooter ruby_bang]$ sudo make install
gcc -Wall -O3 -o ruby_bang ruby_bang.c
/usr/bin/install ruby_bang /bin/ruby_bang
#!/bin/ruby_bang 2.2.0 do ruby
puts RUBY_VERSION$ chmod 755 myscript.rb
$ ./my_script.rb
2.2.0
- Have you been pulling your hair out, trying to get a shebang script to work with RVM?
- Do you want to use multiple scripts in a crontab with different rubies?
- Are you running Linux with wonky argument passing to shebang executables?
- (
#!/usr/bin/env rvm 2.2.0 do rubyactually works on OSX )
- (
- Do you want to use bundler (Gemfile) with your shebang script?
Then this is the app for YOU!
ruby_bang is a very simple wrapper to RVM. It first searches
a few common spots where RVM might be installed. $PATH, $HOME/.rvm/bin, and /usr/local/rvm/bin/rvm.
After it finds an RVM installation, it splits the text after the shebang executable
into space delimited arguments. ruby_bang then takes those arguments and calls execve to the RVM script.
Your ruby script's name (ARGV[0]) is passed to RVM as the last argument.
Some scripts just need a little extra jazz with a bundle. ruby_bang will automatically bundle check
and bundle install if the parameters after do have a bundle exec in them.
Here's an example:
#!/bin/ruby_bang 2.1.1 do bundle exec ruby
require "curb"
curl=Curl::Easy.new
curl.url = "http://google.com"
curl.perform
puts curl.body_str
source "https://rubygems.org"
gem 'curb'
$ ./curl.rb
Fetching gem metadata from https://rubygems.org/..
Resolving dependencies...
Installing curb (0.9.3)
Using bundler (1.5.3)
Your bundle is complete!
Use `bundle show [gemname]` to see where a bundled gem is installed.
<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<TITLE>301 Moved</TITLE></HEAD><BODY>
<H1>301 Moved</H1>
The document has moved
<A HREF="http://www.google.com/">here</A>.
</BODY></HTML>
The bundle check output is hidden, and the next time you run the script with a correct bundle:
$ ./curl.rb
<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<TITLE>301 Moved</TITLE></HEAD><BODY>
...
In various attempts at trying tricks to use bash and RVM as a shebang interpreter, I found that the ruby parser kicks out this error:
ruby: no Ruby script found in input (LoadError)
If the shebang line does not contain the word ruby in the beginning of the executable name, the ruby parser seems to
think it's not a ruby script. Here's one attempt I tried:
#!/bin/bash
''''exec rvm 2.1.1 do ruby -i -- "$0" ${1+"$@"} # '''
puts RUBY_VERSION
And, another proof of concept:
#!/bin/judge_fudge
puts RUBY_VERSION
$ ruby fudge.rb
ruby: no Ruby script found in input (LoadError)
Here are some more advanced examples:
#!/bin/ruby_bang 1.9.3,2.2.0 do ruby
puts RUBY_VERSION
$ ./myscript.rb
1.9.3
2.2.0
$ rvm use ruby-2.1.1
$ rvm gemset create mygems
$ gem install curb
#!/bin/ruby_bang 2.1.1@mygems do ruby
require "curb"
curl=Curl::Easy.new
...
#!/bin/ruby_bang 1.9.3 do ruby
puts ARGV.inspect
$ ./argv.rb one two three four
["one", "two", "three", "four"]