Regex for MAC address

Note

The backreference \1 makes every separator match the first, so mixed colons and dashes are rejected.

Matches in the example

• "00:1A:2B:3C:4D:5E"
• "00-1a-2b-3c-4d-5f"

Token by token

1. \b a word boundary
2. [0-9A-Fa-f]{2} one of: “0” to “9”, “A” to “F” or “a” to “f”, exactly 2 times
3. (?: a group, not capturing
4. ( a capturing group
5. [:-] one of: “:” or “-”
6. ) end of group
7. [0-9A-Fa-f]{2} one of: “0” to “9”, “A” to “F” or “a” to “f”, exactly 2 times
8. ) end of group
9. (?: a group, not capturing
10. \1 the same text group 1 matched
11. [0-9A-Fa-f]{2} one of: “0” to “9”, “A” to “F” or “a” to “f”, exactly 2 times
12. ){4} end of group, whole group exactly 4 times
13. \b a word boundary

Other patterns

• Email address
• URL
• IPv4 address
• UUID
• Hex color
• Date (YYYY-MM-DD)
• Time (24-hour)
• US phone number
• Phone number (E.164)
• US ZIP code
• Credit card number
• URL slug
• Username
• Strong password
• HTML tag
• Semantic version
• MAC address
• JSON Web Token
• Hashtag
• @mention
• Number
• Leading and trailing whitespace
• Repeated word
• Blank lines
• Markdown link
• Quoted string
• Domain name
• File extension
• Base64
• Trailing comma