刪除rc狀態的包

ubuntu下，用apt-get remove 某個軟件包後，用dpkg -l 查看，有些包變成rc 狀態
rc狀態的意思是：

r: the package is marked for removal.    
    c: the configuration files are currently present in the system

要想完全刪除，能夠用如下命令：

dpkg -l | grep ^rc | cut -d' ' -f3| sudo xargs dpkg -P

或：

dpkg --list | grep "^rc" | cut -d " " -f 3 | xargs sudo dpkg --purge

man dpkg有這樣的說明：

-r, --remove, -P, --purge package...|-a|--pending
          Remove  an  installed  package.  -r  or --remove remove everything except conffiles. This may avoid having to
          reconfigure the package if it is reinstalled later. (Conffiles are configuration files that are listed in the
          DEBIAN/conffiles  control file). -P or --purge removes everything, including conffiles. If -a or --pending is
          given instead of a package name, then all packages unpacked, but marked to  be  removed  or  purged  in  file
          /var/lib/dpkg/status, are removed or purged, respectively. Note: some configuration files might be unknown to
          dpkg because they are created and handled separately through the configuration scripts. In  that  case,  dpkg
          won't  remove  them by itself, but the package's postrm script (which is called by dpkg), has to take care of
          their removal during purge. Of course, this only applies to files in system  directories,  not  configuration
          files written to individual users' home directories.

          Removing of a package consists of the following steps:

          1. Run prerm script

          2. Remove the installed files

          3. Run postrm script