freebsd-dev/usr.sbin/pkg_install/delete/pkg_delete.1

.\"
.\" FreeBSD install - a package for the installation and maintainance
.\" of non-core utilities.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" Jordan K. Hubbard
.\"
.\"
.\"     @(#)pkg_delete.1
.\"
.Dd November 25, 1994
.Dt pkg_delete 1
.Os FreeBSD 2.0
.Sh NAME
.Nm pkg_delete
.Nd a utility for deleting previously installed software package distributions
.Sh SYNOPSIS
.Nm
.Op Fl vDdnf
.Op Fl p Ar prefix
.Ar pkg-name ...
.Sh DESCRIPTION
The
.Nm
command is used to delete packages that have been previously installed
with the
.Xr pkg_add 1
command.

.Sh WARNING
.Bf -emphasis
Since the
.Nm
command may execute scripts or programs provided by a package file,
your system may be susceptible to ``trojan horses'' or other subtle
attacks from miscreants who create dangerous package files.
.Pp
You are advised to verify the competence and identity of those who
provide installable package files.  For extra protection, examine all
the package control files in the package record directory (
.Pa /var/db/pkg/<pkg-name>/ ).
Pay particular attention to any +INSTALL, +POST-INSTALL, +DEINSTALL,
+POST-DEINSTALL, +REQUIRE or +MTREE_DIRS files, and inspect the +CONTENTS
file for
.Cm @cwd ,
.Cm @mode 
(check for setuid),
.Cm @dirrm ,
.Cm @exec ,
and
.Cm @unexec
directives, and/or use the
.Xr pkg_info 1
command to examine the installed package control files.
.Ef

.Sh OPTIONS
The following command line options are supported:
.Bl -tag -width indent
.It Ar pkg-name ...
The named packages are deinstalled.
.It Fl v
Turn on verbose output.
.It Fl D
If a deinstallation script exists for a given package, do not execute it.
.It Fl n
Don't actually deinstall a package, just report the steps that
would be taken if it were.
.It Fl p Ar prefix
Set
.Ar prefix
as the directory in which to delete files from any installed packages
which do not explicitly set theirs.  For most packages, the prefix will
be set automatically to the installed location by
.Xr pkg_add 1 .
.It Fl d
Remove empty directories created by file cleanup.  By default, only
files/directories explicitly listed in a package's contents (either as
normal files/directories or with the
.Cm @dirrm
directive) will be removed at deinstallation time.  This option tells
.Nm
to also remove any directories that were emptied as a result of removing
the package.  
.It Fl f
Force removal of the package, even if a dependency is recorded or the
deinstall or require script fails.
.El

.Pp
.Sh TECHNICAL DETAILS
.Nm pkg_delete
does pretty much what it says.  It examines installed package records in 
.Pa /var/db/pkg/<pkg-name> ,
deletes the package contents, and finally removes the package records.
.Pp
If a package is required by other installed packages,
.Nm
will list those dependent packages and refuse to delete the package
(unless the
.Fl f
option is given).
.Pp
If the package contains a
.Ar require
file (see 
.Xr pkg_create 1 ),
then this is executed first as
.Bd -filled -offset indent -compact
.Cm require
.Ar <pkg-name>
.Ar DEINSTALL
.Ed
(where
.Ar pkg-name
is the name of the package in question and
.Ar DEINSTALL
is a keyword denoting that this is a deinstallation)
to see whether or not deinstallation should continue.  A non-zero exit
status means no, unless the
.Fl f
option is specified.
.Pp
If a
.Cm deinstall
script exists for the package, it is executed before any files are removed.
It is this script's responsibility to clean up any additional messy details
around the package's installation, since all
.Nm
knows how to do is delete the files created in the original distribution.
The
.Nm deinstall
script is called as:
.Bd -filled -offset indent -compact
.Cm script
.Ar <pkg-name>
.Ar DEINSTALL
.Ed
where
.Ar pkg-name
is the name of the package in question and
.Ar DEINSTALL
is a keyword denoting this as the pre-deinstallation phase.

.Cm Note:
The
.Ar DEINSTALL
keyword will not appear if separate scripts for deinstall and post-deinstall
are given during package creation time (using the
.Cm Fl k
and 
.Cm Fl K
flags to 
.Xr pkg_create 1 ).
.Pp
If a
.Cm post-deinstall
script exists for the package, it is executed
.Cm after
all files are removed.  It is this script's responsibility to clean up any
additional messy details around the package's installation, and leave the
system (hopefully) in the same state that it was prior to the installation
of the package.

The
.Nm post-deinstall
script is called as:
.Bd -filled -offset indent -compact
.Cm script
.Ar <pkg-name>
.Ar POST-DEINSTALL
.Ed
where
.Ar pkg-name
is the name of the package in question and
.Ar POST-DEINSTALL
is a keyword denoting this as the post-deinstallation phase.

.Cm Note:
The
.Ar POST-DEINSTALL
keyword will not appear if separate scripts for deinstall and post-deinstall
are given during package creation time (using the
.Cm Fl k
and 
.Cm Fl K
flags to 
.Xr pkg_create 1 ).

Reasoning behind passing keywords such as
.Ar DEINSTALL
and
.Ar POST-DEINSTALL
is that it lets you potentially write only one program/script that handles
all aspects of installation and deletion.

But experience has proved that this is a lot more difficult to maintain and
is not as advantageous as having separate scripts that handle each aspect of
installation and deinstallation.
.Pp
All scripts are called with the environment variable
.Ev PKG_PREFIX
set to the installation prefix (see the
.Fl p
option above).  This allows a package author to write a script
that reliably performs some action on the directory where the package
is installed, even if the user might have changed it by specifying the
.Fl p
option when running
.Nm
or
.Cm pkg_add .
.Sh SEE ALSO
.Xr pkg_add 1 ,
.Xr pkg_create 1 ,
.Xr pkg_info 1 ,
.Xr mktemp 3 ,
.Xr mtree 8
.Sh AUTHORS
.An Jordan Hubbard
for most of the work.
.An John Kohl
for NetBSD refinements.
.Sh BUGS
Sure to be some.