root@server1:~#aptitude install at
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Reading extended state information      
Initializing package states... Done
Building tag database... Done      
The following partially installed packages will be configured:
  at 
0 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0B of archives. After unpacking 0B will be used.
Writing extended state information... Done
Setting up at (3.1.10ubuntu4) ...
update-rc.d: /etc/init.d/atd: file does not exist
dpkg: error processing at (--configure):
 subprocess post-installation script returned error exit status 1
Errors were encountered while processing:
 at
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install.  Trying to recover:
Setting up at (3.1.10ubuntu4) ...
update-rc.d: /etc/init.d/atd: file does not exist
dpkg: error processing at (--configure):
 subprocess post-installation script returned error exit status 1
Errors were encountered while processing:
 at
Reading package lists... Done             
Building dependency tree       
Reading state information... Done
Reading extended state information      
Initializing package states... Done
Building tag database... Done      
root@server1:~#