First Steps in Pattern Matching

Define a regular expression as a formal language for specifying search patterns in text.

Use an interactive tool like Regex101 to test and debug patterns against sample text.

Write a pattern to find a literal string (e.g., 'ABC-123') in a sample email.

Use the dot (.) metacharacter to match any single character in a pattern.

Escape metacharacters with a backslash (\) to match them literally (e.g., \. to find a period).

Use character sets ([]) to match one of several specified characters (e.g., Ref[-:]123).