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.\" Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org>
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.Dd Jul 11, 2015
.Dt JEXEC 8
.Os
.Sh NAME
.Nm jexec
.Nd "execute a command inside an existing jail"
.Sh SYNOPSIS
.Nm
.Op Fl l
.Op Fl u Ar username | Fl U Ar username
.Ar jail Op Ar command ...
.Sh DESCRIPTION
The
.Nm
utility executes
.Ar command
inside the
.Ar jail
identified by its jid or name.
If
.Ar command
is not specified then the user's shell is used.
.Pp
The following options are available:
.Bl -tag -width indent
.It Fl l
Execute in a clean environment.
The environment is discarded except for
.Ev HOME , SHELL , TERM , USER ,
and anything from the login class capability database for the user.
.It Fl u Ar username
The user name from host environment as whom the
.Ar command
should run.
.It Fl U Ar username
The user name from jailed environment as whom the
.Ar command
should run.
.El
.Sh SEE ALSO
.Xr jail_attach 2 ,
.Xr jail 8 ,
.Xr jls 8
.Sh HISTORY
The
.Nm
utility was added in
.Fx 5.1 .
.Sh BUGS
If the jail is not identified by
.Ar jid
there is a possible race in between the lookup of the jail
and executing the command inside the jail.
Giving a
.Ar jid
has a similar race as another process can stop the jail and
start another one after the user looked up the
.Ar jid .