plays the current macro for the given number of times. If the optional argument times is not specified, you can enter it on the input line.
A (possibly iterated) macro execution terminates as soon as its stream of instructions is exhausted, or one of its commands returns an error. This means that, for instance, you can perform some complex operation on all the lines containing a certain pattern by recording a macro that searches for the pattern and performs the operation, and then playing it a preposterously huge number of times.
Execution of a macro can be interrupted by Control-\.