uname -a will give us this info.FreeBSD sonce.rasca.net 10.0-RELEASE FreeBSD 10.0-RELEASE #0 r260789: Thu Jan 16 22:34:59 UTC 2014 root@snap.freebsd.org:/usr/obj/usr/src/sys/GENERIC amd64
# $FreeBSD: release/10.0.0/etc/mail/mailer.conf 93858 2002-04-05 04:25:14Z gshapiro $
#
# Execute the Postfix sendmail program, named /usr/sbin/sendmail
#
sendmail /usr/sbin/sendmail
send-mail /usr/sbin/sendmail
mailq /usr/sbin/sendmail
newaliases /usr/sbin/sendmail
INST_BASE=on
sendmail /usr/libexec/sendmail/sendmail
send-mail /usr/libexec/sendmail/sendmail
mailq /usr/libexec/sendmail/sendmail
newaliases /usr/libexec/sendmail/sendmail
hoststat /usr/libexec/sendmail/sendmail
purgestat /usr/libexec/sendmail/sendmail
pkg deinstall postfix does not change everything back.