^start of string
*the literal (3210 / 408 / 2016) , repeated any number of times
Dthe literal D (6810 / 1048 / 4416) (case sensitive)
*the literal (3210 / 408 / 2016) , repeated any number of times
Ethe literal E (6910 / 1058 / 4516) (case sensitive)
Group 1( *[A-Za-z0-9]){20} {20}repeats the group contents below exactly 20 times:
*the literal (3210 / 408 / 2016) , repeated any number of times
Character Class[A-Za-z0-9] A-Zone character from A (6510) to Z (9010) (case sensitive)
a-zone character from a (9710) to z (12210) (case sensitive)
0-9one character from 0 (4810) to 9 (5710)
*the literal (3210 / 408 / 2016) , repeated any number of times
$end of string, or before its final line terminator