On receiving SIGUSR1 R will save the workspace and quit.
SIGUSR2 has the same result except that the .Last
function and on.exit expressions will not be called.
kill -USR1 pid
kill -USR2 pidThe process ID of the R process.
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.
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.
Sys.getpid to report the process ID for future use.