regex101: PCRE (Legacy) Substitution Workspace

Pro

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

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

Positive Lookbehind(?<=")

"the literal " (34₁₀ / 42₈ / 22₁₆)

Group 1((?!mailto:)(?:[a-z]*:\/\/)?(?:\S+(?::\S*)?@)?(?:(?:(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\x{a1}-\x{ffff}0-9]+-?)*[a-z\x{a1}-\x{ffff}0-9]+)(?:\.(?:[a-z\x{a1}-\x{ffff}0-9]+-?)*[a-z\x{a1}-\x{ffff}0-9]+)*(?:\.(?:[a-z\x{a1}-\x{ffff}]{2,})))|localhost)(:\d{2,5})?(?:\/(?:[^\s/]*/)*[^\s/.]+)?)

Negative Lookahead(?!mailto:)

mailto:the literal text mailto: (case insensitive)

Non-Capturing Group(?:[a-z]*:\/\/)?

?repeats the group contents below at most once:

Character Class[a-z]*

*matches any number of characters from the set below:

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

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Non-Capturing Group(?:\S+(?::\S*)?@)?

?repeats the group contents below at most once:

\S+any non-whitespace character, repeated at least once

Non-Capturing Group(?::\S*)?

?repeats the group contents below at most once:

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\S*any non-whitespace character, repeated any number of times

@the literal @ (64₁₀ / 100₈ / 40₁₆)

Non-Capturing Group(?:(?:(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\x{a1}-\x{ffff}0-9]+-?)*[a-z\x{a1}-\x{ffff}0-9]+)(?:\.(?:[a-z\x{a1}-\x{ffff}0-9]+-?)*[a-z\x{a1}-\x{ffff}0-9]+)*(?:\.(?:[a-z\x{a1}-\x{ffff}]{2,})))|localhost)

1st Alternative(?:(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\x{a1}-\x{ffff}0-9]+-?)*[a-z\x{a1}-\x{ffff}0-9]+)(?:\.(?:[a-z\x{a1}-\x{ffff}0-9]+-?)*[a-z\x{a1}-\x{ffff}0-9]+)*(?:\.(?:[a-z\x{a1}-\x{ffff}]{2,})))

Non-Capturing Group(?:(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\x{a1}-\x{ffff}0-9]+-?)*[a-z\x{a1}-\x{ffff}0-9]+)(?:\.(?:[a-z\x{a1}-\x{ffff}0-9]+-?)*[a-z\x{a1}-\x{ffff}0-9]+)*(?:\.(?:[a-z\x{a1}-\x{ffff}]{2,})))

1st Alternative(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))

Non-Capturing Group(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])

1st Alternative[1-9]\d?

Character Class[1-9]

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

\d?optionally matches a digit

2nd Alternative1\d\d

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

\da digit

3rd Alternative2[01]\d

2the literal 2 (50₁₀ / 62₈ / 32₁₆)

Character Class[01]

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

1the literal 1 (49₁₀ / 61₈ / 31₁₆)

\da digit

4th Alternative22[0-3]

22the literal text 22

Character Class[0-3]

0-3one character from 0 (48₁₀) to 3 (51₁₀)

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

{2}repeats the group contents below exactly 2 times:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

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

1st Alternative1?\d{1,2}

1?optionally matches the literal 1 (49₁₀ / 61₈ / 31₁₆)

\d{1,2}a digit, repeated between 1 and 2 times

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 Alternative25[0-5]

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

2nd Alternative(?:(?:[a-z\x{a1}-\x{ffff}0-9]+-?)*[a-z\x{a1}-\x{ffff}0-9]+)(?:\.(?:[a-z\x{a1}-\x{ffff}0-9]+-?)*[a-z\x{a1}-\x{ffff}0-9]+)*(?:\.(?:[a-z\x{a1}-\x{ffff}]{2,}))

2nd Alternativelocalhost

Group 2(:\d{2,5})?

Non-Capturing Group(?:\/(?:[^\s/]*/)*[^\s/.]+)?

Positive Lookahead(?=")

Global pattern flags

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

25 tokens

Regular Expression

(?i)(?<=")((?!mailto:)(?:[a-z]*:\/\/)?(?:\S+(?::\S*)?@)?(?:(?:(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\x{a1}-\x{ffff}0-9]+-?)*[a-z\x{a1}-\x{ffff}0-9]+)(?:\.(?:[a-z\x{a1}-\x{ffff}0-9]+-?)*[a-z\x{a1}-\x{ffff}0-9]+)*(?:\.(?:[a-z\x{a1}-\x{ffff}]{2,})))|localhost)(:\d{2,5})?(?:\/(?:[^\s/]*/)*[^\s/.]+)?)(?=")

New

<a href="https://www.example.com/slug1/page">1</a><br/>
<a href="https://www.example.com/slug2/page">2</a><br/>
<a href="https://www.example.com/slug1/page/">3</a><br/>
<a href="https://www.example.com/slug2/page/">4</a><br/>
<a href="https://www.example.com/">5</a><br/>
<a href="https://www.example.com">5b</a><br/>
<a href="https://www.example.com/style.css">6</a><br/>
<a href="https://www.example.com/style.jpg">7</a><br/>
<a href="https://www.example.com/style.png">8</a><br/>
<a href="https://www.example.com/style.pdf">9</a><br/>

Substitution

$1/

<a href="https://www.example.com/slug1/page">1</a><br/>
<a href="https://www.example.com/slug2/page">2</a><br/>
<a href="https://www.example.com/slug1/page/">3</a><br/>
<a href="https://www.example.com/slug2/page/">4</a><br/>
<a href="https://www.example.com/">5</a><br/>
<a href="https://www.example.com">5b</a><br/>
<a href="https://www.example.com/style.css">6</a><br/>
<a href="https://www.example.com/style.jpg">7</a><br/>
<a href="https://www.example.com/style.png">8</a><br/>
<a href="https://www.example.com/style.pdf">9</a><br/>