Linux Regex: Match Two Characters

In Linux, you can use metacharacters of regular expressions to match two characters, the specific method is as follows:

1. Use curly braces {} to match specified repeated characters. For example, to match two consecutive numbers, you can use the regular expression \d{2}.
2. Use parentheses () to indicate a character group, and use a vertical line | to indicate an “or” relationship. For example, to match two consecutive numbers or two consecutive letters, you can use the regular expression (\d{2}|[a-zA-Z]{2}).
3. To escape characters and prevent them from being interpreted as special characters in regular expressions, use the backslash \. For example, to match two consecutive periods ., you can use the regular expression …
4. You can also use character classes [] and quantifiers + to match two characters. For example, to match two consecutive lowercase letters, you can use the regular expression [a-z]{2}.

The above are some common methods, you can choose the most appropriate method based on specific matching needs.