NAMEbreak - Exit from within a for, while, until, or select loop
Exit from within a for, while, until, or select loop. If n is specified, break n levels. n must be >= 1. If n is greater than the number of enclosing loops, all enclosing loops are exited. The return value is 0 unless n is not greater than or equal to 1.
This is extracted from the main bash man page, see there for more details.