Regular Expressions 101

(?i)applies the following effective flags to the remainder of the pattern: gmi

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

^start of line

Character Class[a-f\d]{2}

{2}matches exactly 2 characters from the set below:

a-fone character from a (97₁₀) to f (102₁₀) (case insensitive)

\da Unicode decimal digit

Group 1([.:-]?)

Character Class[.:-]?

?matches at most one character from the set below:

.the literal . (46₁₀ / 56₈ / 2E₁₆)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Group 2([a-f\d]{2}\1){4}

{4}repeats the group contents below exactly 4 times:

Character Class[a-f\d]{2}

{2}matches exactly 2 characters from the set below:

a-fone character from a (97₁₀) to f (102₁₀) (case insensitive)

\da Unicode decimal digit

\1the text saved by group 1

Character Class[a-f\d]{2}

{2}matches exactly 2 characters from the set below:

a-fone character from a (97₁₀) to f (102₁₀) (case insensitive)

\da Unicode decimal digit

$end of line

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

(?i)^[a-f\d]{2}([.:-]?)([a-f\d]{2}\1){4}[a-f\d]{2}$

New

01:02:03:04:ab:cd
definitely:not:a:mac
01-02-03-04-ab-cd
01.23.45.67.89.ab
0123456789ab
0000000:::::00000
0123456789abcdef: