Regular Expressions 101

\ban ASCII word boundary

Group 1(0*(25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}

{3}repeats the group contents below exactly 3 times:

0*the literal 0 (48₁₀ / 60₈ / 30₁₆) , repeated any number of times

Group 2(25[0-5]|2[0-4]\d|[01]?\d\d?)

1st Alternative25[0-5]

25the literal text 25

Character Class[0-5]

0-5one character from 0 (48₁₀) to 5 (53₁₀)

2nd Alternative2[0-4]\d

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Character Class[0-4]

0-4one character from 0 (48₁₀) to 4 (52₁₀)

\da digit

3rd Alternative[01]?\d\d?

Character Class[01]?

?matches at most one character from the set below:

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

\da digit

\d?optionally matches a digit

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group 3(0*(25[0-5]|2[0-4]\d|[01]?\d\d?))

0*the literal 0 (48₁₀ / 60₈ / 30₁₆) , repeated any number of times

Group 4(25[0-5]|2[0-4]\d|[01]?\d\d?)

1st Alternative25[0-5]

25the literal text 25

Character Class[0-5]

0-5one character from 0 (48₁₀) to 5 (53₁₀)

2nd Alternative2[0-4]\d

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Character Class[0-4]

0-4one character from 0 (48₁₀) to 4 (52₁₀)

\da digit

3rd Alternative[01]?\d\d?

Character Class[01]?

?matches at most one character from the set below:

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

\da digit

\d?optionally matches a digit

\ban ASCII word boundary

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

\b(0*(25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(0*(25[0-5]|2[0-4]\d|[01]?\d\d?))\b

Test String
New

1.1.1.1
2.2.2.2
10.10.10.10
100.100.100.100
125.125.125.125
250.250.250.250
255.255.255.255
0101.0101.0101.0101
00000102.00000102.00000102.00000102
0.0.0.0

256.256.256.256
1234.1234.1234.1234

Regular Expression

Test StringNew

Test String
New