+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
, matches the character , with index 44_{10} (2C_{16} or 54_{8}) literally (case sensitive)
Match a single character present in the list below [0-9]
{3} matches the previous token exactly 3 times
0-9 matches a single character in the range between 0 (index 48) and 9 (index 57) (case sensitive)