NetBSD/share/man/man8/rescue.8

.\"	$NetBSD: rescue.8,v 1.5 2009/01/20 04:10:38 lukem Exp $
.\"
.\" Copyright (c) 2003 Tim Kientzle <kientzle@acm.org>
.\" Copyright (c) 2003 Simon L. Nielsen <simon@FreeBSD.org>
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.\"  FreeBSD: src/share/man/man8/rescue.8,v 1.3 2005/11/10 15:42:51 kientzle Exp
.\"
.Dd January 20, 2009
.Os
.Dt RESCUE 8
.Sh NAME
.Nm rescue
.Nd rescue utilities in
.Pa /rescue
.Sh DESCRIPTION
The
.Pa /rescue
directory contains a collection of common utilities intended for use
in recovering a badly damaged system.
With the transition to a dynamically-linked root beginning with
.Nx 2.0 ,
there is a real possibility that the standard tools in
.Pa /bin
and
.Pa /sbin
may become non-functional due to a failed upgrade or a disk error.
The tools in
.Pa /rescue
are statically linked and should therefore be more resistant to
damage.
However, being statically linked, the tools in
.Pa /rescue
are also less functional than the standard utilities.
In particular, they do not have full use of the locale,
.Xr pam 3 ,
and nsswitch libraries.
.Pp
If your system fails to boot, and it shows an error message similar to:
.Pp
.Dl "init: not found"
.Pp
try booting the system with the boot flag
.Dq Fl a
and supplying
.Pa /rescue/init ,
which is the
.Nm
.Xr init 8 ,
as the init path.
.Pp
If your system fails to boot, and it shows a prompt similar to:
.Pp
.Dl "Enter full pathname of shell or RETURN for /bin/sh: "
.Pp
the first thing to try running is the standard shell,
.Pa /bin/sh .
If that fails, try running
.Pa /rescue/sh ,
which is the
.Nm
shell.
To repair the system, the root partition must first be remounted
read-write.
This can be done with the following
.Xr mount 8
command:
.Pp
.Dl "/rescue/mount -uw /"
.Pp
The next step is to double-check the contents of
.Pa /bin ,
.Pa /lib ,
.Pa /libexec ,
and
.Pa /sbin ,
possibly mounting a
.Nx
installation CD-ROM
and copying files from there.
Once it is possible to successfully run
.Pa /bin/sh , /bin/ls ,
and other standard utilities, try rebooting back into the standard
system.
.Pp
The
.Pa /rescue
tools are compiled using
.Xr crunchgen 1 ,
which makes them considerably more compact than the standard
utilities.
.Sh FILES
.Bl -tag -width ".Pa /rescue" -compact
.It Pa /rescue
Root of the
.Nm
hierarchy.
.El
.Sh SEE ALSO
.Xr crunchgen 1
.Sh HISTORY
The
.Nm
utilities first appeared in
.Nx 2.0 .
.Sh AUTHORS
.An -nosplit
The
.Nm
system was written by
.An Luke Mewburn Aq lukem@NetBSD.org .
This manual page was written by
.An Simon L. Nielsen Aq simon@FreeBSD.org ,
based on text by
.An Tim Kientzle Aq kientzle@FreeBSD.org .
.Sh BUGS
Most of the
.Nm
tools work even in a fairly crippled system.
The most egregious exception is the
.Nm
version of
.Xr vi 1 ,
which currently requires that
.Pa /usr
be mounted so that it can access the
.Xr termcap 5
files.
Hopefully, a failsafe
.Xr termcap 3
entry will eventually be added into the
.Xr curses 3
library, so that
.Pa /rescue/vi
can be used even in a system where
.Pa /usr
cannot immediately be mounted.
In the meantime, the
.Nm
version of the
.Xr ed 1
editor can be used from
.Pa /rescue/ed
if you need to edit files, but cannot mount
.Pa /usr .