re = /[^m]>/
str = '<test@gmail.com>
>Lorem ipsum dolor sit amet,<test@gmail.com> consectetur
>adipiscing elit. Integer nec >
>odio. Praesent libero. Sed cursus ante dapibus diam. Sed nisi. Nulla
>quis sem at nibh elementum imperdiet.Duis sagittis ipsum. Praesent
>mauris. Fusce nec tellus sed augue semper porta. Mauris massa.
>Vestibulum lacinia arcu eget nulla. Class aptent taciti sociosqu.
<test@gmail.com>'
subst = ''
result = str.gsub(re, subst)
# Print the result of the substitution
puts result
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html