Regular Expression Note

symbol	description
.	$x=1$
?	$x==1\shortmid x==0$
+	$x\geq 1$
*	$x\geq 0$
{n}	$x=n$
{min,}	$x\geq min$
{min,max}	$min<x<max$
$[ ]$	Match a single character in
$[\text{^} ]$	Match a single character not in