Regular Expressions 101

^start of line

\[the literal [ (91₁₀ / 133₈ / 5B₁₆)

Negated Character Class[^\]]+

+matches at least one character outside the set below:

\]the literal ] (93₁₀ / 135₈ / 5D₁₆)

Condition(?(?=\s*;)\s*;.*|$)

Uses the first branch if the lookaround matches

Positive Lookahead(?=\s*;)

\s*any whitespace character, repeated any number of times

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

If the condition is true, match this branch:\s*;.*

\s*any whitespace character, repeated any number of times

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

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

Otherwise, match this branch:$

$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

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

^\[[^\]]+\](?(?=\s*;)\s*;.*|$)

New

[asd]
[asd];
[asd]  ;
[asd]asd
[asdf];asd
[some;thing]
 - Valid, with capture group some;thing
[something]
 - Valid, with capture group something
 [something]
 - Invalid, does not begin with 

[something] ;ojasodj
 - Valid, capture group something

[something]  
- Invalid, space after ] without a ; present

[something];
 - Valid, capture group something

Regular Expression

Extraction