Ruby: make gems available to your command-line .rb script

If you add a require line to a command line Ruby script, like this:

require 'tzinfo'

…it will fail to find the library unless you’ve done one of the steps below.

Include rubygems at runtime

When running your script, use:

ruby -rubygems my_program_that_uses_gems

Easier: set the RUBYOPT environment variable to always include gems

Edit .bash_profile and add:

export RUBYOPT=rubygems

Easiest: include rubygems on your shebang line

#!/usr/bin/ruby -rubygems

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