如遇到如下问题：
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:
git : Depends: liberror-perl but it is not going to be installed
Depends: git-man (> 1:2.7.4) but it is not going to be installed
Depends: git-man (< 1:2.7.4-.) but it is not going to be installed
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).
可尝试：
sudo apt-get update --> update package informatio
sudo apt-get dist-upgrade --> upgrade packages on system
sudo apt-get -f install --> fix broken packages
然后：
sudo apt-get install ruby 一般就可以了。