======RPM======
=====List Installed Patched=====
List all installed patched and include the date stamp of when they were installed.
<code>rpm -qa --queryformat '%{installtime}  \"%{vendor}\" %{name}-%{version}-%{release}  %{installtime:date}\n' | sort -n</code>
=====Install History=====
List the installation history of PACKAGENAME.
<code>rpm -qa --queryformat '%{NAME} || %{INSTALLTIME:date}\n' | grep PACKAGENAME</code>
=====List Files Associated with RPM=====
<code>rpm -qlp file.rpm</code>
=====RPM Downgrade=====
<code>rpm -Uvh --oldpackage oldversion.rpm</code>
<code>yum downgrade oldversion.rpm</code>
=====List all installed patches (with date stamp)=====
<code>rpm -qa --queryformat '%{installtime}  \"%{vendor}\" %{name}-%{version}-%{release}  %{installtime:date}\n' | sort -n</code>
=====Force Uninstall=====
<code>rpm -e packagename --noscripts</code>
=====Install RPM Forge CentOS 7=====
<code>wget http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.3-1.el7.rf.x86_64.rpm
rpm -Uvh rpmforge-release-0.5.3-1.el7.rf.x86_64.rpm</code>
=====Install RPM Forge CentOS 6=====
<code>wget http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.3-1.el6.rf.x86_64.rpm
rpm -Uvh rpmforge-release-0.5.3-1.el6.rf.x86_64.rpm</code>

=====Install EPEL Repository on CentOS 6=====
<code>wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
rpm -Uvh epel-release-6-8.noarch.rpm</code>

=====Install EPEL Repository on CentOS 7=====
<code>wget http://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-5.noarch.rpm
rpm -Uvh epel-release-7-5.noarch.rpm</code>