Regular Expressions 101

Explanation
Pro

Character Class[[:space:]]*

*matches any number of characters from the set below:

[:space:]a whitespace character, including a line break [ \t\r\n\v\f]

Group 1([_[:alnum:]]*)

Character Class[_[:alnum:]]*

*matches any number of characters from the set below:

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

[:alnum:]an alphanumeric character [a-zA-Z0-9]

Character Class[[:space:]]*

*matches any number of characters from the set below:

[:space:]a whitespace character, including a line break [ \t\r\n\v\f]

=the literal = (61₁₀ / 75₈ / 3D₁₆)

Character Class[[:space:]]*

*matches any number of characters from the set below:

[:space:]a whitespace character, including a line break [ \t\r\n\v\f]

Group 2((.*?)[[:space:]]+([_[:alnum:]]+[[:space:]]*=[[:space:]]*.*))

Group 3(.*?)

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

Character Class[[:space:]]+

+matches at least one character from the set below:

[:space:]a whitespace character, including a line break [ \t\r\n\v\f]

Group 4([_[:alnum:]]+[[:space:]]*=[[:space:]]*.*)

Character Class[_[:alnum:]]+

+matches at least one character from the set below:

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

[:alnum:]an alphanumeric character [a-zA-Z0-9]

Character Class[[:space:]]*

*matches any number of characters from the set below:

[:space:]a whitespace character, including a line break [ \t\r\n\v\f]

=the literal = (61₁₀ / 75₈ / 3D₁₆)

Character Class[[:space:]]*

*matches any number of characters from the set below:

[:space:]a whitespace character, including a line break [ \t\r\n\v\f]

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

Detailed match information will be displayed here automatically.

25 tokens

[[:space:]]*([_[:alnum:]]*)[[:space:]]*=[[:space:]]*((.*?)[[:space:]]+([_[:alnum:]]+[[:space:]]*=[[:space:]]*.*))

New

key1 = what' ever the value key2 = the value Nb.2 key3= "last value"