Learn how to use POSIX regular expressions with grep via the Linux Command Line.
What are regular expressions (regex)? What is the linux command line's POSIX standard to regex?
Learn about literal characters and special (meta) characters. We'll have an overview look at both Basic Regular Expressions (BRE) and Extended Regular Expressions (ERE).
Learn how you can use Basic Regular Expressions to match single characters with a period, literal character, an escape key, or bracket expansion.
Learn how you can use bracket expressions to specify from a group of characters. Additionally, we'll go over portability issues, character classes, and non-English environments.
Learn how to match multiple characters with the wildcard symbol and braces.
Learn how you can reference an earlier character set with backreferences. Also learn about anchors, which are useful for specifying when some text should come at the beginning or end of a regular expression.
Learn additional features made available by extended regular expressions.