Regular Expressions 101

Group 1(localhost|127.0.0.1|192.168.[0-9]{1,3}\.[0-9]{1,3})

1st Alternativelocalhost

localhostthe literal text localhost (case insensitive)

2nd Alternative127.0.0.1

127the literal text 127

.any character (except for line terminators)

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

.any character (except for line terminators)

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

.any character (except for line terminators)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

3rd Alternative192.168.[0-9]{1,3}\.[0-9]{1,3}

192the literal text 192

.any character (except for line terminators)

168the literal text 168

.any character (except for line terminators)

Character Class[0-9]{1,3}

{1,3}matches between 1 and 3 characters from the set below:

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

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Character Class[0-9]{1,3}

{1,3}matches between 1 and 3 characters from the set below:

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

:?optionally matches the literal : (58₁₀ / 72₈ / 3A₁₆)

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

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

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

(localhost|127.0.0.1|192.168.[0-9]{1,3}\.[0-9]{1,3}):?

New

localhost
localhost:4444
127.0.0.1
127.0.0.1:1111
192.168.1.1
192.168.1.1:1111