# URL Rules

This section allows you to create custom rules for checking and modifying URL parameters. Each rule is described by the following components:

• Parameter: The name of the parameter in the link to be checked or modified.
• Operator: The specific check or operation to be performed.
• Argument: The operator's argument if applicable (macros are supported).
• "On" Switch: Allows you to enable or disable individual rules.

The following operators are supported:

• EXISTS : Checks if the parameter exists (the argument is ignored).
• NOT EXISTS : Checks if the parameter does not exist (the argument is ignored).
• REGEX : Checks the parameter for a match with a Perl-compatible regular expression (PCRE) in the argument (case-sensitive).
• REGEX (no case) : Checks the parameter for a match with a regular expression in the argument (case-insensitive).
• NOT REGEX : Checks the parameter for no match with a regular expression in the argument (case-sensitive).
• NOT REGEX(no case) : Checks the parameter for no match with a regular expression in the argument (case-insensitive).
• =, ≠, >, ≥, <, ≤: Compares the parameter with the argument; integer and floating-point values are compared as numbers, strings are compared lexically.
• ASSIGN : Assigns the parameter the value from the argument.
• RENAME : Renames the parameter to the argument.
• DELETE : Removes the parameter from the link (the argument is ignored).

The rules are executed in the following order:

• Checks: EXISTS , REGEX , =, ≠, >, ≥, <, ≤. A failed check sends to the white page.
• ASSIGN rules.
• RENAME rules.
• DELETE rules.