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

Non-Capturing Group(?:([a-z0-9-]+|\*)\.)?

?repeats the group contents below at most once:

Group 1([a-z0-9-]+|\*)

1st Alternative[a-z0-9-]+

Character Class[a-z0-9-]+

+matches at least one character from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case insensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

2nd Alternative\*

\*the literal * (42₁₀ / 52₈ / 2A₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group 2([a-z0-9-]{1,61})

Character Class[a-z0-9-]{1,61}

{1,61}matches between 1 and 61 characters from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case insensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group 3([a-z0-9]{2,7})

Character Class[a-z0-9]{2,7}

{2,7}matches between 2 and 7 characters from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case insensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

$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-z0-9-]+|\*)\.)?([a-z0-9-]{1,61})\.([a-z0-9]{2,7})$

New

website.com
www.website.com
*.website.com
*x.website.com
x*.website.com
**.website.com
website.aaaaaaaaaaa
totally-not.a-sketchy.site
bad_website.com
web-site.net

Regular Expression

Extraction