SIGUSR1 R will save the workspace and quit.
SIGUSR2 has the same result except that the
on.exit expressions will not be called.
kill -USR1 pid kill -USR2 pid
The process ID of the R process.
The commands history will also be saved if would be at normal termination.
This is not available on Windows, and possibly on other OSes which do not support these signals.
It is possible that one or more R objects will be undergoing modification at the time the signal is sent. These objects could be saved in a corrupted form.
Sys.getpid to report the process ID for future use.