15th
Ruby: gem which
I just stumbled across this today while doing some work on RCor:
gem which Find the location of a library file you can require
Ok, so why is that useful?
Lets say you’re working on some ruby code with a line like:
require ‘concordion_test_case’
But ‘concordion_test_case’ isn’t in the project (which runs), so you deduce it must come from a gem.
For example: Rails applications are notorious for bundling all gem dependencies into ‘environment.rb’. This can obscure which gem is used to fulfill the dependency.
The question is: which one? The command “gem which” can solve this problem:
$ gem which concordion_test_case
(checking gem rcor-0.9.3 for concordion_test_case)
/usr/lib/ruby/gems/1.8/gems/rcor-0.9.3/lib/concordion_test_case.rb
The output will vary on different installations of ruby/gem, but the important bit to note is it told us which gem (& version) defines the symbol: “rcor-0.9.3”.
