Adding and Removing Software:

  Each operating systems is shipped with its own version of "package
  management software".  This software typically has a way for the
  administrator to query the list of installed packages, remove a
  package, test the integrity of a package, and add packages.  As
  with many elements of the UNIX system, each vendor has reinvented
  the wheel and has a completely different way of operating their
  package management software.  Here is a quick rundown on some of the
  tools:

    rpm:   RedHat Package Manager          (RedHat Linux)
    dpkg:  Debian Package Manager          (Debian Linux)
    pkg*:  Solaris Package Management Tools (Solaris)
    cvsup: FreeBSD Package Management Tool (FreeBSD)

  In most cases, the package consists of a single file, with a unique
  file type --- most are glorified tar archives (see tar(1)).  They
  contain some scripts that perform setup (some software [especially
  network services] need corresponding entries in system files to
  be usable), others that will remove the software, and sometimes
  scripts for configuring the software when you add it.  The more
  sophisticated package management software tools will even check
  dependencies (other packages that the software needs to run).

  The short story is that none of these tools are perfect, and all
  share a common flaw:  they are distributed by a different group
  than the group that designed the tools.  The big problem with
  this is that there is always a time delay before new software
  is produced (bundled) into vendor package files, and that the
  people who wrote the configuration scripts may not be adequately
  expert with the software.  The end result is that you will almost
  always have to do post-install configuration.

  Because you will almost always have to manually configure software,
  I recommend that you use the vendor packaging tools as little as
  possible --- use them to install the base system, and little more.
  The rule of thumb is:  if you may want to upgrade the software before
  the next revision of the operating system comes out, don't use
  the vendor package.  Software that falls into this category includes
  some editors (emacs, but not vi --- emacs includes "feature
  enhancements" every 5 months or so), most of your network daemons
  (sendmail in particular), and most of your visualization tools.
  The X11 software is something that you should let the vendor software
  install and upgrade --- X11 software often includes some very
  hardware dependent configuration --- the vendor will have written
  good tools for setting it up.

  There are also a set of commercial software packages that you
  don't have any option but to install with their tools.  Most of
  the time, they don't use the vendor package management software,
  but instead have a configuration script that you run, and then
  an install script that puts the software where they want it to
  be.

  I recommend that you pay very careful attention to the software
  that is installed on your machines.  Don't install software unless
  you know that you are interested in using it, and remove the software
  as soon as you are sure you won't use it.  This will keep you from
  having software that might have security problems on your system, and
  it will conserve resources (disk space, and possibly cpu and network
  bandwidth).

  Whenever possible, I recommend getting the source code for your
  software from the maintainer of the software.  This will let you
  compile the software on your own machine, and tune any configuration
  parameters that might need to be set at compile time.