^start of line
Group 1(([012][0-9])|(3[01])) 1st Alternative([012][0-9]) 0the literal 0 (4810 / 608 / 3016)
1the literal 1 (4910 / 618 / 3116)
2the literal 2 (5010 / 628 / 3216)
0-9one character from 0 (4810) to 9 (5710)
3the literal 3 (5110 / 638 / 3316)
0the literal 0 (4810 / 608 / 3016)
1the literal 1 (4910 / 618 / 3116)
-the literal - (4510 / 558 / 2D16)
0the literal 0 (4810 / 608 / 3016)
1-9one character from 1 (4910) to 9 (5710)
1the literal 1 (4910 / 618 / 3116)
0the literal 0 (4810 / 608 / 3016)
1the literal 1 (4910 / 618 / 3116)
2the literal 2 (5010 / 628 / 3216)
-the literal - (4510 / 558 / 2D16)
\da digit
\da digit
\da digit
\da digit
the literal (3210 / 408 / 2016)
Character Class[012]{0,1} {0,1}matches at most one character from the set below:
0the literal 0 (4810 / 608 / 3016)
1the literal 1 (4910 / 618 / 3116)
2the literal 2 (5010 / 628 / 3216)
0-9one character from 0 (4810) to 9 (5710)
:the literal : (5810 / 728 / 3A16)
0-6one character from 0 (4810) to 6 (5410)
0-9one character from 0 (4810) to 9 (5710)
:the literal : (5810 / 728 / 3A16)
0-6one character from 0 (4810) to 6 (5410)
0-9one character from 0 (4810) to 9 (5710)
$end of line
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