# $Id: README,v 8.2 2009/10/15 22:22:17 ksb Exp $

Install is a tool for updating system files in a  controlled
environment.   The  design philosophy of install is to automate the
installation process and put  it  as  much  out  of reach  of  human
carelessness as possible, while providing a flexible, easy to use
tool.

Install provides the  following features:

 o    Install increases system security by providing  a  con-
      trolled   installation   environment.   It  checks  the
      actions of the superuser against a  configuration  file
      that  you  build  (either by hand or using instck(1L)),
      and can prevent grievous mistakes such as installing  a
      shell  setuid  to  a  privileged  user, or installing a
      world-writable password file.   An  appropriate  confi-
      guration  file  can  guarantee that files are installed
      with correct owner, group and mode,  that  strip(1)  is
      run  on  binaries  and  ranlib(1)  is run on libraries.
      Regardless of whether you create a configuration  file,
      install  warns  you of many possible errors, unless you
      make it quiet with its -q option.  For instance, if you
      install a new version of the ex(1) editor and forget to
      update its links, install will notice the  extra  links
      to  the existing version and warn you that you might be
      making a mistake.

 o    Installed files do not overwrite current versions.  The
      current  version  is backed up to a subdirectory of its
      dot directory (named "OLD" by default), where it may be
      easily  re-installed  in  the case of an unforseen bug.
      The companion program purge(1L) removes these backed-up
      files  after a user-specified interval.  By default, if
      you repeatedly install new versions of a file,  install
      creates a series of backups, providing a primitive form
      of version control.

 o    Install increases accountability by logging the actions
      of  the  superuser.  This makes it easier to track down
      errors after the fact.

 o    Install simplifies Makefiles by allowing you to combine
      operations that would require several steps into a sin-
      gle one (e.g., you can specify in a single command line
      a   file's  ownership,  group,  mode,  whether  to  run
      strip(1) or ranlib(1), and which  hard  or  soft  links
      should be made).

 o    Despite its power and potential complexity, install  is
      easy  to use interactively because it intuits appropri-
      ate installation parameters for you,  either  by  using
      those   associated  with  the  existing  file,  or  its
      compilation-dependent defaults.  In most cases  you  do
      not  have  to  specify  a  file's owner, group, or mode
      unless you want them to be different from  an  existing
      file.   Typical  interactive  usage  is simply "install
      file destination."

 o    Install is as careful as  it  can  be  to  complete  an
      installation once it is begun.  There is a point in the
      code where unlink(2) and rename(2) must be executed  in
      close  succession, and that is the only window in which
      a system crash or a signal might leave system files  in
      an  inconsistent state (unfortunately, this is not true
      under operating systems that do not provide  an  atomic
      rename(2) system call).  This is true even when install
      must copy files across file system boundaries.

 o    Install may also be used to remove  (de-install)  files
      in a controlled manner.

 o    Finally, install currently runs on a variety of  archi-
      tectures  and  operating systems and is easy to port to
      new platforms.


Known bugs, or problems:

None.  Unless you miss the flags crazyness in FreeBSD.  If you do, you
might send me a patch to do them.

--
kayessbee, install@ksb.npcguild.org, Kevin S Braunsdorf