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.\"     from: @(#)chroot.8	8.1 (Berkeley) 6/9/93
.\"
.Dd $Mdocdate: May 31 2007 $
.Dt CHROOT 8
.Os
.Sh NAME
.Nm chroot
.Nd change root directory
.Sh SYNOPSIS
.Nm chroot
.Op Fl g Ar group,group,...
.Op Fl u Ar user
.Ar newroot
.Op Ar command
.Sh DESCRIPTION
The
.Nm
command changes its root directory to the supplied directory
.Ar newroot
and executes
.Ar command ,
if supplied, or an interactive copy of the user's shell.
.Pp
The
.Nm
command is restricted to the superuser.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl g Ar group,group,...
Override the primary and supplemental group IDs.
The primary group ID is set to the first group in the list.
Any remaining groups are placed in the supplemental group ID vector.
Each group listed must exist in the
.Xr group 5
databases.
.It Fl u Ar user
Set user ID to
.Ar user
(which must exist in the
.Xr passwd 5
database).
The primary and supplemental group IDs will be set based on the user's
entries in the
.Xr passwd 5
and
.Xr group 5
databases unless overridden by the
.Fl g
option.
.El
.Sh ENVIRONMENT
.Bl -tag -width SHELL
.It Ev SHELL
If set,
the string specified by
.Ev SHELL
is interpreted as the name of
the shell to execute.
If the variable
.Ev SHELL
is not set,
.Pa /bin/sh
is used.
.El
.Sh SEE ALSO
.Xr chdir 2 ,
.Xr chroot 2 ,
.Xr setgid 2 ,
.Xr setgroups 2 ,
.Xr setuid 2 ,
.Xr group 5 ,
.Xr passwd 5 ,
.Xr environ 7
.Sh HISTORY
The
.Nm
utility first appeared in
.Bx 4.4 .
.Sh CAVEATS
.Nm
should never be installed setuid root, as it would then be possible
to exploit the program to gain root privileges.