I wanted to install a package on CentOS 6 via rpm (e.g., the current epel-release). EDIT: Of course I would always prefer the installation via yum but somehow I failed to get that specific package installed using this normal approach. As such, the EPEL/FAQ recommends Version 2. As I'm downloading the package through an insecure channel (http) I wanted to make sure that the integrity of the file is verified using information that is not provided with the downloaded file itself. Is this especially true for all of these approaches? I've seen various approaches to this on the internet: Version 1 rpm -ivh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-7.noarch.rpm Version 2 rpm -Uvh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-7.noarch.rpm Version 3 wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-7.noarch.rpm rpm --import https://fedoraproject.org/static/0608B895.txt rpm -K epel-release-6-7.noarch.rpm rpm -i epel-release-6-7.noarch.rpm I do not know rpm very well, so I wondered how they might differ? My guess (after reading the manpage) is that the first should only be used when the package is previously not installed, the second would additionally remove previous versions of the package after installation, the first two omit some verification steps before the actual installation that are done by rpm -K. So my main questions at this point are Are my guesses correct or am I missing something? Is the rpm --import ... implicitly done for the first two approaches as well, and if not, isn't it necessary to do so after all? Are these additional checks performed by rpm -K ... any relevant? What is the best (most secure, most reliable, most maintainable, ...) way of installing packages via rpm in general?