1.\" Copyright (c) 1988, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)chroot.8 8.1 (Berkeley) 6/9/93 29.\" $FreeBSD$ 30.\" 31.Dd March 14, 2019 32.Dt CHROOT 8 33.Os 34.Sh NAME 35.Nm chroot 36.Nd change root directory 37.Sh SYNOPSIS 38.Nm 39.Op Fl G Ar group Ns Op Cm \&, Ns Ar group ... 40.Op Fl g Ar group 41.Op Fl u Ar user 42.Ar newroot 43.Op Ar command Op Ar arg ... 44.Sh DESCRIPTION 45The 46.Nm 47utility changes its current and root directories to the supplied directory 48.Ar newroot 49and then exec's 50.Ar command 51with provided arguments, if supplied, 52or an interactive copy of the user's login shell. 53.Pp 54The options are as follows: 55.Bl -tag -width "-G group[,group ...]" 56.It Fl G Ar group Ns Op Cm \&, Ns Ar group ... 57Run the command with the permissions of the specified groups. 58.It Fl g Ar group 59Run the command with the permissions of the specified 60.Ar group . 61.It Fl u Ar user 62Run the command as the 63.Ar user . 64.El 65.Sh ENVIRONMENT 66The following environment variable is referenced by 67.Nm : 68.Bl -tag -width "SHELL" 69.It Ev SHELL 70If set, 71the string specified by 72.Ev SHELL 73is interpreted as the name of 74the shell to exec. 75If the variable 76.Ev SHELL 77is not set, 78.Pa /bin/sh 79is used. 80.El 81.Sh EXAMPLES 82.Bl -tag -width 0n 83.It Sy Example 1\&: No Chrooting into a New Root Directory 84.Pp 85The following command opens the 86.Xr csh 1 87shell after chrooting to the standard root directory. 88.Bd -literal -offset 2n 89.Li # Ic chroot / /bin/csh 90.Ed 91.It Sy Example 2\&: No Execution of a Command with a Changed Root Directory 92.Pp 93The following command changes a root directory with 94.Nm 95and then runs 96.Xr ls 1 97to list the contents of 98.Pa /sbin . 99.Bd -literal -offset 2n 100.Li # Ic chroot /tmp/testroot ls /sbin 101.Ed 102.El 103.Sh SEE ALSO 104.Xr chdir 2 , 105.Xr chroot 2 , 106.Xr setgid 2 , 107.Xr setgroups 2 , 108.Xr setuid 2 , 109.Xr getgrnam 3 , 110.Xr environ 7 , 111.Xr jail 8 112.Sh HISTORY 113The 114.Nm 115utility first appeared in 116.Bx 4.4 . 117