/etc/init.d/ssh restart
sudo service ssh restart
sudo restart ssh

sudo stop ssh
sudo start ssh

ps -ef | grep sshd

root      1234     1  0 12:28 ?        00:00:00 /usr/sbin/sshd -D

cat /var/run/sshd.pid

userid@computername:~$ cat /var/run/sshd.pid
1234

ps ax | grep sshd

/usr/sbin/sshd -D