Network Security Tools

Comparison Operators

Here are the common comparison operators:

>

Used to test whether a given value is greater than the other.

>=

Used to test whether a given value is greater than or equal to the other.

<

Used to test whether a given value is less than the other.

<=

Used to test whether a given value is less than or equal to the other.

==

Used to test whether a given value is equal to the other.

!=

Used to test whether a given value is not equal to the other.

><

Used to test whether a given substring exists within a string. For example, '123'><'abcd123def' evaluates to TRUE.

>!<

Used to test whether a given substring does not exist within a string. In this case, '123'>!<'abcd123def' evaluates to FALSE.

=~

Used to match a regular expression. Using this operator is similar to calling the ereg( ) function call, which performs a similar operation. For example, the statement str =~ '^[GET / HTTP/1.0\r\n\r\n][.]*') evaluates to TRUE only if str begins with the string GET / HTTP/1.0\r\n\r\n.

!~

Used to test whether a regular expression does not match. It is the opposite of the =~ operator.

[]

Used to select a character from a string by index. For example, if mystring is a1b2c3, mystring[3] evaluates to 2.