'\" te
.\" Copyright (c) 2004, Sun Microsystems, Inc. All Rights Reserved.
.\" Copyright 1989 AT&T
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.TH CHROOT 1M "Dec 15, 2003"
.SH NAME
chroot \- change root directory for a command
.SH SYNOPSIS
.LP
.nf
\fB/usr/sbin/chroot\fR \fInewroot\fR \fIcommand\fR
.fi

.SH DESCRIPTION
.sp
.LP
The \fBchroot\fR utility causes \fIcommand\fR to be executed relative to
\fInewroot\fR. The meaning of any initial slashes (\fB\|/\|\fR) in the path
names is changed to \fInewroot\fR for \fIcommand\fR and any of its child
processes. Upon execution, the initial working directory is \fInewroot\fR.
.sp
.LP
Notice that redirecting the output of \fIcommand\fR to a file,
.sp
.in +2
.nf
chroot\fI newroot \|command\fR >\fBx\fR
.fi
.in -2
.sp

.sp
.LP
will create the file \fBx\fR relative to the original root of \fIcommand\fR,
not the new one.
.sp
.LP
The new root path name is always relative to the current root. Even if a
\fBchroot\fR is currently in effect, the \fInewroot\fR argument is relative to
the current root of the running process.
.sp
.LP
This command can be run only by the super-user.
.SH RETURN VALUES
.sp
.LP
The exit status of \fBchroot\fR is the return value of \fIcommand\fR.
.SH EXAMPLES
.LP
\fBExample 1 \fRUsing the \fBchroot\fR Utility
.sp
.LP
The \fBchroot\fR utility provides an easy way to extract \fBtar\fR files (see
\fBtar\fR(1)) written with absolute filenames to a different location. It is
necessary to copy the shared libraries used by \fBtar\fR (see \fBldd\fR(1)) to
the \fInewroot\fR filesystem.

.sp
.in +2
.nf
example# mkdir /tmp/lib; cd /lib
example# cp ld.so.1 libc.so.1 libcmd.so.1 libdl.so.1 \e
         libsec.so.1 /tmp/lib
example# cp /usr/bin/tar /tmp
example# dd if=/dev/rmt/0 | chroot /tmp tar xvf -
.fi
.in -2
.sp

.SH SEE ALSO
.sp
.LP
\fBcd\fR(1), \fBtar\fR(1), \fBchroot\fR(2), \fBttyname\fR(3C),
\fBattributes\fR(5)
.SH NOTES
.sp
.LP
Exercise extreme caution when referencing device files in the new root file
system.
.sp
.LP
References by routines such as \fBttyname\fR(3C) to stdin, stdout, and stderr
will find that the device associated with the file descriptor is unknown after
\fBchroot\fR is run.