1.\" Copyright (c) 2003 Tim Kientzle <kientzle@acm.org> 2.\" Copyright (c) 2003 Simon L. Nielsen <simon@FreeBSD.org> 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd June 30, 2022 29.Dt RESCUE 8 30.Os 31.Sh NAME 32.Nm rescue 33.Nd rescue utilities in 34.Pa /rescue 35.Sh DESCRIPTION 36The 37.Pa /rescue 38directory contains a collection of common utilities intended for use 39in recovering a badly damaged system. 40With the transition to a dynamically-linked root beginning with 41.Fx 5.2 , 42there is a real possibility that the standard tools in 43.Pa /bin 44and 45.Pa /sbin 46may become non-functional due to a failed upgrade or a disk error. 47The tools in 48.Pa /rescue 49are statically linked and should therefore be more resistant to 50damage. 51However, being statically linked, the tools in 52.Pa /rescue 53are also less functional than the standard utilities. 54In particular, they do not have full use of the locale, 55.Xr pam 3 , 56and nsswitch libraries. 57.Pp 58If your system fails to boot, and it shows a prompt similar to: 59.Pp 60.Dl "Enter full pathname of shell or RETURN for /bin/sh: " 61.Pp 62the first thing to try running is the standard shell, 63.Pa /bin/sh . 64If that fails, try running 65.Pa /rescue/sh , 66which is the 67.Nm 68shell. 69To repair the system, the root partition must first be remounted 70read-write. 71This can be done with the following 72.Xr mount 8 73command: 74.Pp 75.Dl "/rescue/mount -uw /" 76.Pp 77The next step is to double-check the contents of 78.Pa /bin , /sbin , 79and 80.Pa /usr/lib , 81possibly mounting a 82.Fx 83rescue or 84.Dq "live file system" 85CD-ROM and copying files from there. 86Once it is possible to successfully run 87.Pa /bin/sh , /bin/ls , 88and other standard utilities, try rebooting back into the standard 89system. 90.Pp 91The 92.Pa /rescue 93tools are compiled using 94.Xr crunchgen 1 , 95which makes them considerably more compact than the standard 96utilities. 97To build a 98.Fx 99system where space is critical, 100.Pa /rescue 101can be used as a replacement for the standard 102.Pa /bin 103and 104.Pa /sbin 105directories; simply change 106.Pa /bin 107and 108.Pa /sbin 109to be symbolic links pointing to 110.Pa /rescue . 111Since 112.Pa /rescue 113is statically linked, it should also be possible to dispense with much 114of 115.Pa /usr/lib 116in such an environment. 117.Pp 118In contrast to its predecessor 119.Pa /stand , 120.Pa /rescue 121is updated during normal 122.Fx 123source and binary upgrades. 124.Sh FILES 125.Bl -tag -width ".Pa /rescue" -compact 126.It Pa /rescue 127Root of the 128.Nm 129hierarchy. 130.El 131.Sh SEE ALSO 132.Xr crunchgen 1 , 133.Xr crash 8 134.Sh HISTORY 135The 136.Nm 137utilities first appeared in 138.Fx 5.2 . 139.Sh AUTHORS 140.An -nosplit 141The 142.Nm 143system was written by 144.An Tim Kientzle Aq Mt kientzle@FreeBSD.org , 145based on ideas taken from 146.Nx . 147This manual page was written by 148.An Simon L. Nielsen Aq Mt simon@FreeBSD.org , 149based on text by 150.An Tim Kientzle Aq Mt kientzle@FreeBSD.org . 151.Sh BUGS 152Most of the 153.Nm 154tools work even in a fairly crippled system. 155The most egregious exception is the 156.Nm 157version of 158.Xr vi 1 , 159which currently requires that 160.Pa /usr 161be mounted so that it can access the 162.Xr termcap 5 163files. 164Hopefully, a failsafe 165.Xr termcap 3 166entry will eventually be added into the 167.Xr ncurses 3 168library, so that 169.Pa /rescue/vi 170can be used even in a system where 171.Pa /usr 172cannot immediately be mounted. 173In the meantime, the 174.Nm 175version of the 176.Xr ed 1 177editor can be used from 178.Pa /rescue/ed 179if you need to edit files, but cannot mount 180.Pa /usr . 181