185 lines
4.5 KiB
Groff
185 lines
4.5 KiB
Groff
.\" Copyright (c) 2003 Tim Kientzle <kientzle@acm.org>
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.\" Copyright (c) 2003 Simon L. Nielsen <simon@FreeBSD.org>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd July 23, 2003
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.Os
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.Dt RESCUE 8
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.Sh NAME
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.Nm rescue
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.Nd rescue utilities in
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.Pa /rescue
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.Sh DESCRIPTION
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The
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.Pa /rescue
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directory contains a collection of common utilities intended for use
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in recovering a badly damaged system.
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With the transition to a dynamically-linked root beginning with
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.Fx 5.2 ,
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there is a real possibility that the standard tools in
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.Pa /bin
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and
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.Pa /sbin
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may become non-functional due to a failed upgrade or a disk error.
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The tools in
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.Pa /rescue
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are statically linked and should therefore be more resistant to
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damage.
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However, being statically linked, the tools in
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.Pa /rescue
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are also less functional than the standard utilities.
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In particular, they do not have full use of the locale,
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.Xr pam 3 ,
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and nsswitch libraries.
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.Pp
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If your system fails to boot, and it shows a prompt similar to:
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.Pp
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.Dl "Enter full pathname of shell or RETURN for /bin/sh: "
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.Pp
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the first thing to try running is the standard shell,
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.Pa /bin/sh .
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If that fails, try running
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.Pa /rescue/sh ,
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which is the
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.Nm
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shell.
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To repair the system, the root partition must first be remounted
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read-write.
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This can be done with the following
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.Xr mount 8
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command:
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.Pp
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.Dl "/rescue/mount -uw /"
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.Pp
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The next step is to double-check the contents of
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.Pa /bin , /sbin ,
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and
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.Pa /usr/lib ,
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possibly mounting a
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.Fx
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rescue or
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.Dq "live file system"
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CD-ROM (e.g.,
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.Li disc2
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of the officially released
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.Fx
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ISO images) and copying files from there.
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Once it is possible to successfully run
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.Pa /bin/sh , /bin/ls ,
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and other standard utilities, try rebooting back into the standard
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system.
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.Pp
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The
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.Pa /rescue
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tools are compiled using
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.Xr crunchgen 1 ,
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which makes them considerably more compact than the standard
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utilities.
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To build a
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.Fx
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system where space is critical,
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.Pa /rescue
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can be used as a replacement for the standard
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.Pa /bin
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and
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.Pa /sbin
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directories; simply change
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.Pa /bin
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and
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.Pa /sbin
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to be symbolic links pointing to
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.Pa /rescue .
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Since
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.Pa /rescue
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is statically linked, it should also be possible to dispense with much
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of
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.Pa /usr/lib
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in such an environment.
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.Pp
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In contrast to its predecessor
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.Pa /stand ,
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.Pa /rescue
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is updated during normal
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.Fx
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source and binary upgrades.
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.Sh FILES
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.Bl -tag -width ".Pa /rescue" -compact
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.It Pa /rescue
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Root of the
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.Nm
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hierarchy.
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.El
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.Sh SEE ALSO
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.Xr crunchgen 1 ,
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.Xr crash 8
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.Sh HISTORY
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The
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.Nm
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utilities first appeared in
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.Fx 5.2 .
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.Sh AUTHORS
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.An -nosplit
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The
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.Nm
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system was written by
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.An Tim Kientzle Aq kientzle@FreeBSD.org ,
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based on ideas taken from
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.Nx .
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This manual page was written by
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.An Simon L. Nielsen Aq simon@FreeBSD.org ,
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based on text by
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.An Tim Kientzle Aq kientzle@FreeBSD.org .
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.Sh BUGS
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Most of the
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.Nm
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tools work even in a fairly crippled system.
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The most egregious exception is the
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.Nm
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version of
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.Xr vi 1 ,
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which currently requires that
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.Pa /usr
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be mounted so that it can access the
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.Xr termcap 5
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files.
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Hopefully, a failsafe
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.Xr termcap 3
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entry will eventually be added into the
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.Xr ncurses 3
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library, so that
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.Pa /rescue/vi
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can be used even in a system where
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.Pa /usr
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cannot immediately be mounted.
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In the meantime, the
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.Nm
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version of the
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.Xr ed 1
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editor can be used from
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.Pa /rescue/ed
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if you need to edit files, but cannot mount
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.Pa /usr .
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