14.1 Signal the Daemon

The sendmail program recognizes three signals that cause it to perform certain actions. SIGINT and SIGTERM cause sendmail to clean up after itself and exit. Beginning with V8.7, SIGHUP causes sendmail to re-execute itself (thus restarting and reading its configuration file anew). Also beginning with V8.7, SIGUSR1 causes sendmail to log its file descriptors and other information.