# apt-get remove quagga
Reading package lists... Done
Building dependency tree... Done
The following packages will be REMOVED:
  quagga
0 upgraded, 0 newly installed, 1 to remove and 2 not upgraded.
1 not fully installed or removed.
Need to get 0B of archives.
After unpacking 4157kB disk space will be freed.
Do you want to continue [Y/n]?
(Reading database ... 21266 files and directories currently installed.)
Removing quagga ...
As requested via Debconf, the Quagga daemon will not stop.
dpkg: error processing quagga (--remove):
 subprocess pre-removal script returned error exit status 1
Loading capability module if not yet done.
Starting Quagga daemons (prio:10): zebra/usr/lib/quagga/zebra already running.
invoke-rc.d: initscript quagga, action "start" failed.
dpkg: error while cleaning up:
 subprocess post-installation script returned error exit status 1
Errors were encountered while processing:
 quagga
E: Sub-process /usr/bin/dpkg returned an error code (1)