regex101: PCRE2 (PHP) Match Workspace

^start of line

Non-Capturing Group(?:(?:(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\.){3}(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])(?:-(?:(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\.){3}(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])|\/(?:[0-9]|[1-2][0-9]|3[0-2]))?|(?:[a-z0-9]+(?:-[a-z0-9]+)*\.)+[a-z]{2,})

1st Alternative(?:(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\.){3}(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])(?:-(?:(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\.){3}(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])|\/(?:[0-9]|[1-2][0-9]|3[0-2]))?

Non-Capturing Group(?:(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\.){3}

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

Non-Capturing Group(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])

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][0-9]

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Character Class[0-4]

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

Character Class[0-9]

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

3rd Alternative1[0-9][0-9]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[0-9]

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

Character Class[0-9]

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

4th Alternative[1-9]?[0-9]

Character Class[1-9]?

?matches at most one character from the set below:

1-9one character from 1 (49₁₀) to 9 (57₁₀)

Character Class[0-9]

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

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Non-Capturing Group(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])

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][0-9]

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Character Class[0-4]

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

Character Class[0-9]

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

3rd Alternative1[0-9][0-9]

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

Character Class[0-9]

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

Character Class[0-9]

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

4th Alternative[1-9]?[0-9]

Character Class[1-9]?

Character Class[0-9]

Non-Capturing Group(?:-(?:(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\.){3}(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])|\/(?:[0-9]|[1-2][0-9]|3[0-2]))?

2nd Alternative(?:[a-z0-9]+(?:-[a-z0-9]+)*\.)+[a-z]{2,}

$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

Search reference

Regular Expression

^(?:(?:(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\.){3}(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])(?:-(?:(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\.){3}(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])|\/(?:[0-9]|[1-2][0-9]|3[0-2]))?|(?:[a-z0-9]+(?:-[a-z0-9]+)*\.)+[a-z]{2,})$

Test String
New

Valid
1.2.3.4
255.255.255.255
1.2.3.4-1.2.3.4
1.2.3.4/24
1.2.3.4/8
www.example.com
www.example.lv
www.example.com

Invalid
1.2.3
1.2.3.
.1.2.3
1.2.3.4/33
www.-example.com
1.2.3.4-1.2.3.256
1.2.3.4.5.6.7.8 (use anchors ^ and $ to skip these if needed)
999.999.999.999 (use a complex regex to skip these if needed)
299.299.299.299
001.002.003.004 (these use octal notation, not decimal)

Regular Expressions 101

Regular Expression

Test String
New

Extraction
Processing...

Regular Expression

Test StringNew

ExtractionProcessing...

Test String
New

Extraction
Processing...