& Logical and. All items in the list must be true, as in (&(a=1)(b=2) ).
| Logical or. One or more of the items must be true, as in (|(a=1)(b=2) ).
! Not. The negated item must be false, as in (!(3=4)) is true.
= Checks for equality based on the matching rule of the attribute.
~= Checks for approximate equality based on the matching rule of the attribute.
>= Checks that the attribute is greater than the value.
<= Checks that the attribute is less than the value.
=* Checks for existence of the attribute.
* In an equality test; represents a wildcard representing zero or more characters at that position, as in (name=Alb*).
\ Used for escaping *, (, and ) inside an attribute value.