Occasionally I get errors during the apt-get upgrade process. Here's a simple solution to one - the 'file or dir already exists' error:
dpkg: error processing /var/cache/apt/archives/package (--install):
trying to overwrite 'file/dir', which is also in package other_package
Errors were encountered while processing:
/var/cache/apt/archives/package
So - here's what to do:
dpkg -i --force-overwrite /var/cache/apt/archives/package