\ban ASCII word boundary
Onthe literal text On (case sensitive) \s+any whitespace character, repeated at least once
Non-Capturing Group(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sept?|Oct|Nov|Dec) Janthe literal text Jan (case sensitive) Febthe literal text Feb (case sensitive) Marthe literal text Mar (case sensitive) Aprthe literal text Apr (case sensitive) Maythe literal text May (case sensitive) Junthe literal text Jun (case sensitive) Julthe literal text Jul (case sensitive) Augthe literal text Aug (case sensitive) Septhe literal text Sep (case sensitive) t?optionally matches the literal t (11610 / 1648 / 7416) (case sensitive)
Octthe literal text Oct (case sensitive) Novthe literal text Nov (case sensitive) Decthe literal text Dec (case sensitive) \s+any whitespace character, repeated at least once
Non-Capturing Group(?:0?[1-9]|[12]\d|3[01]) 0?optionally matches the literal 0 (4810 / 608 / 3016)
1-9one character from 1 (4910) to 9 (5710)
1the literal 1 (4910 / 618 / 3116)
2the literal 2 (5010 / 628 / 3216)
\da digit
3the literal 3 (5110 / 638 / 3316)
0the literal 0 (4810 / 608 / 3016)
1the literal 1 (4910 / 618 / 3116)
,the literal , (4410 / 548 / 2C16)
\s*any whitespace character, repeated any number of times
\d{4}a digit, repeated exactly 4 times
\s*any whitespace character, repeated any number of times
Non-Capturing Group(?:0?[0-9]|1[0-2]) 0?optionally matches the literal 0 (4810 / 608 / 3016)
0-9one character from 0 (4810) to 9 (5710)
1the literal 1 (4910 / 618 / 3116)
0-2one character from 0 (4810) to 2 (5010)
:the literal : (5810 / 728 / 3A16)
\s*any whitespace character, repeated any number of times
M,the literal text M, (case sensitive) 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