How to remove several lines in the Vim editor using Regex

A quick tip for those who use Vim: if you need to remove several lines that match your regular expression, you can achive that by running

viml
:g /pattern/d

Let's say you want to remove the commented lines from the following file:

ruby
# This is a comment
def foo
end

# This is another comment
def bar
end

Run :g /^#.*/d and your code will become:

ruby
def foo
end

def bar
end

Simple, hey? :)