Add Evaluating One-Off Commands as a ruby til.

README.md

@@ -62,6 +62,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 - [Are They All True?](ruby/are-they-all-true.md)
 - [Create an Array of Stringed Numbers](ruby/create-an-array-of-stringed-numbers.md)
 - [Destructuring Arrays In Blocks](ruby/destructuring-arrays-in-blocks.md)
+- [Evaluating One-Off Commands](ruby/evaluating-one-off-commands.md)
 - [Finding The Source of Ruby Methods](ruby/finding-the-source-of-ruby-methods.md)
 - [Limit Split](ruby/limit-split.md)
 - [Parallel Bundle Install](ruby/parallel-bundle-install.md)

ruby/evaluating-one-off-commands.md

@@ -0,0 +1,11 @@
+# Evaluating One-Off Commands
+
+When I need to quickly test something out in Ruby, I will often reach for
+`irb`. There is an even quicker way to send a line of code to ruby for
+evaluation. Use the `ruby` binary with the `-e` flag followed by your line
+of ruby. For instance,
+
+```
+$ ruby -e 'puts Class.ancestors'
+[Class, Module, Object, Kernel, BasicObject]
+```