Это аргумент для quit()
.См. ?quit
.
Аргументы :
status: the (numerical) error status to be returned to the operating
system, where relevant. Conventionally ‘0’ indicates
successful completion.
Подробности :
Some error statuses are used by R itself. The default error
handler for non-interactive use effectively calls ‘q("no", 1,
FALSE)’ and returns error code 1. Error status 2 is used for R
‘suicide’, that is a catastrophic failure, and other small numbers
are used by specific ports for initialization failures. It is
recommended that users choose statuses of 10 or more.