For more information, see Using Your Assigned Administrative Rights in Securing Users and Processes in Oracle Solaris 11.2 .
# /usr/lib/sendmail -qRstring
Use a recipient's alias or a substring of firstname.lastname@example.org, such as a host name.
Alternately, you can run a subset of the mail queue with –qInnnnn.
# /usr/lib/sendmail -qInnnnn
Use a queue ID.