RedHat (Older than version 9) - up2date
RedHat Based (RH9, Fedora, CentOS, RHEL, ect) - yum
Debian Based (Debian, *buntu) - apt-get
Portage Based (Gentoo) - emerge
Ports Based (OpenBSD, FreeBSD, NetBSD) - pkg_add
Source - Download .tar, .tar.gz, or .tar.bz2 than use tar to extract (tar xf, tar xzf, tar xjf)