ubuntu@ubuntu:~$ sudo apt-get purge openssh-server && sudo apt-get clean && sudo apt-get install openssh-server
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
  openssh-server*
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
After this operation, 834 kB disk space will be freed.
Do you want to continue [Y/n]? y
(Reading database ... 159187 files and directories currently installed.)
Removing openssh-server ...
stop: Unknown job: ssh
Purging configuration files for openssh-server ...
Processing triggers for ufw ...
Processing triggers for ureadahead ...
Processing triggers for man-db ...
Reading package lists... Done
Building dependency tree
Reading state information... Done
Suggested packages:
  rssh molly-guard openssh-blacklist openssh-blacklist-extra monkeysphere
The following NEW packages will be installed:
  openssh-server
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 340 kB of archives.
After this operation, 834 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu/ quantal/main openssh-server amd64 1:6.0p1-3ubuntu1 [340 kB]
Fetched 340 kB in 6s (55.4 kB/s)
Preconfiguring packages ...
Selecting previously unselected package openssh-server.
(Reading database ... 159170 files and directories currently installed.)
Unpacking openssh-server (from .../openssh-server_1%3a6.0p1-3ubuntu1_amd64.deb) ...
Processing triggers for man-db ...
Processing triggers for ureadahead ...
Processing triggers for ufw ...
Setting up openssh-server (1:6.0p1-3ubuntu1) ...
Creating SSH2 RSA key; this may take some time ...
Creating SSH2 DSA key; this may take some time ...
Creating SSH2 ECDSA key; this may take some time ...
initctl: Unknown job: ssh
start: Unknown job: ssh
Processing triggers for ureadahead ...
Processing triggers for ufw ...