-i

Invoke utility with exactly the environment specified by the arguments; the inherited environment shall be ignored completely.

name=value

Arguments of the form name= value shall modify the execution environment, and shall be placed into the inherited environment before the utility is invoked.

utility

The name of the utility to be invoked. If the utility operand names any of the special built-in utilities in Section 2.14, Special Built-In Utilities, the results are undefined.

argument

A string to pass as an argument for the invoked utility.