A popular
distribution of the
Linux operating system as of 2001 A.D. Many
distributions utilize the Redhat Package Manager, or
RPM, to handle
software installation and maintenance.
Redhat is characterized by a strong software package management utility (RPM), a System V-style init process, a flexible OS installation process that can scale from holding a newbie's hand to performing automated, unattended server installation. Redhat also includes graphical utilities that allow those not familiar with the command line to easily administer the system.
Many Linux geeks are bitter towards Redhat, claiming that Redhat is geared towards newbies due to the available GUI administration tools. This is generally due to the inexperience of the luser making such claims. Any guru understands that Linux is fundamentally Linus Torvalds' kernel combined with GNU tools. All other distribution-provided utilities are essentially superfluous. If you can grok one Linux distribution, you can grok them all.
As a sidenote to these GUIs that Redhat includes, the databases that they store their configuration data in are often very similar to the textual files that other UNIXen operating systems utilize. It is trivial to configure the system using either.