When I enter
sudo apt-get install unity tweak I get this message:
***Errors were encountered while processing: runit git-daemon-run E: Sub-process /usr/bin/dpkg returned an error code (1)***
You just typing it wrong it should be:
sudo apt install unity-tweak-tool
Sure you would agree that the system is telling you something isn't right is a good thing, sadly it doesn't really do that in a satisfactory way.
To prevent future mishaps like this you can simply use
apt-cache search to get the proper package name.
apt-cache search unity-tweak
will result in this:
$ apt-cache search unity-tweak unity-tweak-tool - configuration tool for the Unity desktop environment