More Basic Regular Expressions: Matching an Email Address

You work for Ethercloud, a web hosting company. Due to scheduled downtime, the support team needs a list of email addresses so that they can contact customers appropriately. Since you have access to a CSV of customer data (customer-data.xt), you've been tasked with retrieving all emails from this data via regular expression and sorting them in alphabetical order. (Hint: Use grep and sort.)

While writing the regular expression, note the following restrictions regarding email address:

• The local-part (or username), can use any alphanumeric character or one of the following: <code>! # $ % & ' * + - / = ? ^ _ ` { | } ~ .</code>
• The second-level domain (gmail in gmail.com) must begin with an alphanumeric character but any character after that can also contain a dash (-).
• The domain must be at least one character long.
• The top-level domain (such as com) must only use alphanumeric characters.
• The top-level domain must be between two and 63 characters.

If you need a list of email addresses to match, try:

test_email@linuxacademy.com
panel.80432@outlook.com
Beauty-90184@yahoo.com
RusticPlasticSausages13@yahoo.com
Facet-o-face29917@yahoo.com