由于种种原因，决定今天开始从centos7转为ubuntu14.0.但是一开始就遇到了一个问题。ubuntu的源貌似被墙了。没有办法，只好换源。如是参考了下面的帖子。
但是又出现了一个问题,百度了好久才找到
zhao@ubuntu:~$ sudo apt-get -f install gcc Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies: gcc : Depends: cpp (>= 4:4.8.2-1ubuntu6) but 4:4.7.3-1ubuntu10 is to be installed Depends: gcc-4.8 (>= 4.8.2-5~) but it is not going to be installed libreoffice-base-core : Depends: libreoffice-core (= 1:4.0.2-0ubuntu1) but 1:4.2.8-0ubuntu2 is to be installed libreoffice-core : Depends: ure (>= 4.2~) but 4.0.2-0ubuntu1 is to be installed Depends: lp-solve (>= 5.5.0.13-5+b1) but it is not going to be installed Depends: libcmis-0.4-4 (>= 0.4.0) but it is not going to be installed Depends: uno-libs3 (>= 4.2.0~rc1) but 4.0.2-0ubuntu1 is to be installed libreoffice-draw : Depends: uno-libs3 (>= 4.1.0~alpha) but 4.0.2-0ubuntu1 is to be installed libreoffice-impress : Depends: uno-libs3 (>= 4.1.0~alpha) but 4.0.2-0ubuntu1 is to be installed Recommends: libreoffice-avmedia-backend-gstreamer but it is not going to be installed libreoffice-math : Depends: libreoffice-core (= 1:4.0.2-0ubuntu1) but 1:4.2.8-0ubuntu2 is to be installed libreoffice-writer : Depends: libreoffice-base-core (= 1:4.2.8-0ubuntu2) but 1:4.0.2-0ubuntu1 is to be installed Depends: uno-libs3 (>= 4.2.0~rc1) but 4.0.2-0ubuntu1 is to be installed python3-uno : Depends: libreoffice-core (= 1:4.0.2-0ubuntu1) but 1:4.2.8-0ubuntu2 is to be installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).
解决方法是：
sudo apt-get install -f
可以愉快的工作了。