Why the use of both <% and <%= in the views?

erb, ruby-on-rails

Solution

`<%=` puts the return value of the code inside to the page.

`<%` just execute code.

Here is the good guide about ERB http://api.rubyonrails.org/classes/ActionView/Base.html

Problem

If I write something like: `<% if signed_in?.blank? %>` or `<%= link_to "Sign Up", sign_up_path %>` What is the difference between the two signs of `<%` and `<%=`? Why make it this way instead of using just one for simplicity? When do I know I need to use `<%` over `<%=`?

Original source