regex

b match b
b+ is match bbbbbbbbbbbbbbbbbbbbbbbbb
+ is 1 or more matches
[bd] is match b d
[bd]+ is match bbbdddbbdbdbdbdbdbd, bbbbbddddddd, bbbbbbbbbb, dddddddddddd
b* bbbbbbbbbbbbbbbbbbbbbbbbb
* is 0 or more matches
[^x] matches everything but x
(ab+|bc+) will match both abbbbbbb and bccccccccccc, its a OR statement
0123456789 \d
abcd....xyz a-z
ABC------XYZ A-Z
\s whitespaces like spaces, tabs
\n for newlines
. is for everything
? is for optional
aaaaaaaaaaaa{10,35}
aaaa{10,}