regex101: PCRE (Legacy) Match Workspace

Negative Lookbehind(?<!\\)

\\the literal \ (92₁₀ / 134₈ / 5C₁₆)

Comment: Check it was not escaped with a \

Group img_all(?<img_all> \!\[(?<img_alt>.+?)\] # image alternative text, i.e. the text used when the image does not (?: (?: [ ]? # possibly followed by some spaces (?:\n[ ]*)? # and a new line with some space \[(?<img_id>.*?)\] # with the link id in brackets, but may be empty ) | (?: (?: $ [ \t]* <(?<img_url> # link url within <>; or .+? )> [ \t]* # possibly followed by some spaces or tabs (?: (?<img_title_container>['"]) # Title is surrounded ether by double or single quotes (?<img_title>.*?) # actual title, but could be empty as in "" \g{img_title_container} # make the sure enclosing mark balance )? [ \t]* $ ) | (?: $ [ \t]* (?<img_url> # link url within <>; or (?:((?!["']).)*+|.*) ) [ \t]* (?: (?<img_title_container>['"]) # Title is surrounded ether by double or single quotes (?<img_title>.*?) # actual title, but could be empty as in "" \g{img_title_container} # make the sure enclosing mark balance )? [ \t]* $ ) ) ) )

\!the literal ! (33₁₀ / 41₈ / 21₁₆)

\[the literal [ (91₁₀ / 133₈ / 5B₁₆)

Group img_alt(?<img_alt>.+?)

.+?any character (except for line terminators), repeated at least once

\]the literal ] (93₁₀ / 135₈ / 5D₁₆)

Comment: image alternative text, i.e. the text used when the image does not

Non-Capturing Group(?: (?: [ ]? # possibly followed by some spaces (?:\n[ ]*)? # and a new line with some space \[(?<img_id>.*?)\] # with the link id in brackets, but may be empty ) | (?: (?: $ [ \t]* <(?<img_url> # link url within <>; or .+? )> [ \t]* # possibly followed by some spaces or tabs (?: (?<img_title_container>['"]) # Title is surrounded ether by double or single quotes (?<img_title>.*?) # actual title, but could be empty as in "" \g{img_title_container} # make the sure enclosing mark balance )? [ \t]* $ ) | (?: $ [ \t]* (?<img_url> # link url within <>; or (?:((?!["']).)*+|.*) ) [ \t]* (?: (?<img_title_container>['"]) # Title is surrounded ether by double or single quotes (?<img_title>.*?) # actual title, but could be empty as in "" \g{img_title_container} # make the sure enclosing mark balance )? [ \t]* $ ) ) )

1st Alternative (?: [ ]? # possibly followed by some spaces (?:\n[ ]*)? # and a new line with some space \[(?<img_id>.*?)\] # with the link id in brackets, but may be empty )

Non-Capturing Group(?: [ ]? # possibly followed by some spaces (?:\n[ ]*)? # and a new line with some space \[(?<img_id>.*?)\] # with the link id in brackets, but may be empty )

Character Class[ ]?

?matches at most one character from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

Comment: possibly followed by some spaces

Non-Capturing Group(?:\n[ ]*)?

?repeats the group contents below at most once:

\na line-feed (newline) character (ASCII 10)

Character Class[ ]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

Comment: and a new line with some space

\[the literal [ (91₁₀ / 133₈ / 5B₁₆)

Group img_id(?<img_id>.*?)

.*?any character (except for line terminators), repeated any number of times

\]the literal ] (93₁₀ / 135₈ / 5D₁₆)

Comment: with the link id in brackets, but may be empty

2nd Alternative (?: (?: $ [ \t]* <(?<img_url> # link url within <>; or .+? )> [ \t]* # possibly followed by some spaces or tabs (?: (?<img_title_container>['"]) # Title is surrounded ether by double or single quotes (?<img_title>.*?) # actual title, but could be empty as in "" \g{img_title_container} # make the sure enclosing mark balance )? [ \t]* $ ) | (?: $ [ \t]* (?<img_url> # link url within <>; or (?:((?!["']).)*+|.*) ) [ \t]* (?: (?<img_title_container>['"]) # Title is surrounded ether by double or single quotes (?<img_title>.*?) # actual title, but could be empty as in "" \g{img_title_container} # make the sure enclosing mark balance )? [ \t]* $ ) )

Non-Capturing Group(?: (?: $ [ \t]* <(?<img_url> # link url within <>; or .+? )> [ \t]* # possibly followed by some spaces or tabs (?: (?<img_title_container>['"]) # Title is surrounded ether by double or single quotes (?<img_title>.*?) # actual title, but could be empty as in "" \g{img_title_container} # make the sure enclosing mark balance )? [ \t]* $ ) | (?: $ [ \t]* (?<img_url> # link url within <>; or (?:((?!["']).)*+|.*) ) [ \t]* (?: (?<img_title_container>['"]) # Title is surrounded ether by double or single quotes (?<img_title>.*?) # actual title, but could be empty as in "" \g{img_title_container} # make the sure enclosing mark balance )? [ \t]* $ ) )

1st Alternative (?: $ [ \t]* <(?<img_url> # link url within <>; or .+? )> [ \t]* # possibly followed by some spaces or tabs (?: (?<img_title_container>['"]) # Title is surrounded ether by double or single quotes (?<img_title>.*?) # actual title, but could be empty as in "" \g{img_title_container} # make the sure enclosing mark balance )? [ \t]* $ )

Non-Capturing Group(?: $ [ \t]* <(?<img_url> # link url within <>; or .+? )> [ \t]* # possibly followed by some spaces or tabs (?: (?<img_title_container>['"]) # Title is surrounded ether by double or single quotes (?<img_title>.*?) # actual title, but could be empty as in "" \g{img_title_container} # make the sure enclosing mark balance )? [ \t]* $ )

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

Character Class[ \t]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

<the literal text <

Group img_url(?<img_url> # link url within <>; or .+? )

Comment: link url within <>; or

.+?any character (except for line terminators), repeated at least once

> the literal text >

Character Class[ \t]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

Comment: possibly followed by some spaces or tabs

Non-Capturing Group(?: (?<img_title_container>['"]) # Title is surrounded ether by double or single quotes (?<img_title>.*?) # actual title, but could be empty as in "" \g{img_title_container} # make the sure enclosing mark balance )?

?repeats the group contents below at most once:

Group img_title_container(?<img_title_container>['"])

Character Class['"]

'the literal ' (39₁₀ / 47₈ / 27₁₆)

"the literal " (34₁₀ / 42₈ / 22₁₆)

Comment: Title is surrounded ether by double or single quotes

Group img_title(?<img_title>.*?)

.*?any character (except for line terminators), repeated any number of times

Comment: actual title, but could be empty as in ""

\g{img_title_container}the text saved by group img_title_container

Comment: make the sure enclosing mark balance

Character Class[ \t]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

\)the literal ) (41₁₀ / 51₈ / 29₁₆)

2nd Alternative (?: $ [ \t]* (?<img_url> # link url within <>; or (?:((?!["']).)*+|.*) ) [ \t]* (?: (?<img_title_container>['"]) # Title is surrounded ether by double or single quotes (?<img_title>.*?) # actual title, but could be empty as in "" \g{img_title_container} # make the sure enclosing mark balance )? [ \t]* $ )

Non-Capturing Group(?: $ [ \t]* (?<img_url> # link url within <>; or (?:((?!["']).)*+|.*) ) [ \t]* (?: (?<img_title_container>['"]) # Title is surrounded ether by double or single quotes (?<img_title>.*?) # actual title, but could be empty as in "" \g{img_title_container} # make the sure enclosing mark balance )? [ \t]* $ )

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

Character Class[ \t]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

Group img_url(?<img_url> # link url within <>; or (?:((?!["']).)*+|.*) )

Character Class[ \t]*

\)the literal ) (41₁₀ / 51₈ / 29₁₆)

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

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

J modifier: Allow duplicate subpattern names

25 tokens

Regular Expression

(?<!\\)                                             # Check it was not escaped with a \
(?<img_all>
    \!\[(?<img_alt>.+?)\]                           # image alternative text, i.e. the text used when the image does not
    (?:
        (?:
            [ ]?                                    # possibly followed by some spaces
            (?:\n[ ]*)?                             # and a new line with some space
            \[(?<img_id>.*?)\]                      # with the link id in brackets, but may be empty
        )
        |
        (?:
            (?:
                \(
                    [ \t]*
                    <(?<img_url>                    # link url within <>; or
                        .+?
                    )>
                    [ \t]*                              # possibly followed by some spaces or tabs
                    (?:
                        (?<img_title_container>['"])    # Title is surrounded ether by double or single quotes
                        (?<img_title>.*?)               # actual title, but could be empty as in ""
                        \g{img_title_container}         # make the sure enclosing mark balance
                    )?
                    [ \t]*
                \)
            )
            |
            (?:
                \(
                    [ \t]*
                    (?<img_url>                    # link url within <>; or
                        (?:((?!["']).)*+|.*)
                    )
                    [ \t]*
                    (?:
                        (?<img_title_container>['"])    # Title is surrounded ether by double or single quotes
                        (?<img_title>.*?)               # actual title, but could be empty as in ""
                        \g{img_title_container}         # make the sure enclosing mark balance
                    )?
                    [ \t]*
                \)
            )
        )
    )
)

New

![Alt text](/path/to/img.jpg)

Inline within a paragraph: ![alt text](/url/).

![this is a stupid URL](http://example.com/(parens).jpg'Title here')

![this is a stupid URL](http://example.com/ (parens).jpg "With title") some text after

![alt text](</url/>)

![Alt text](/path/to/img.jpg)

Extraction

![Alt text](/path/to/img.jpg)

Inline within a paragraph: ![alt text](/url/).

![this is a stupid URL](http://example.com/(parens).jpg'Title here')

![this is a stupid URL](http://example.com/ (parens).jpg "With title") some text after

![alt text](</url/>)

![Alt text](/path/to/img.jpg)