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.Dd December 4, 2019
.Dt MOUNT_DEVFS 8
.Os
.Sh NAME
.Nm mount_devfs
.Nd mount a device file system
.Sh SYNOPSIS
.Nm
.Op Fl o Ar options
.Ar node
.Sh DESCRIPTION
The
.Nm
command attaches an instance of the device file system (or
.Xr devfs 5 )
to the global file system namespace.
This command is automatically executed for
.Pa /dev
at boot time.
.Pp
The options are as follows:
.Bl -tag -width indent
.It Fl o
Specify mount options, which are a comma delimited set of options (see
.Xr mount 8 ) .
Supported mount options are:
.Bl -tag -width indent
.It Ar jail
Mount
.Xr devfs 5
for a jail.
Only rules between
.Ic jail Ar yes
and
.Ic jail Ar no
are applied.
.It Ar ruleset=rule_file
When mounting, apply the rules from the specified
.Ar rule_file ,
which can be either an absolute path or one relative to
.Pa /etc/devfs/ .
.El
.El
.Pp
Mounting an already mounted
.Ar node
clears and resets all rules that are in effect for it and (if a
.Ar ruleset
option is present) applies the rules from
.Ar rule_file .
It is equal to
.Nm devfsctl Fl cr
followed by an optional
.Nm devfsctl Fl af .
.Sh EXAMPLES
Mount a
.Xr devfs 5 ,
marked as
.Ar jail ,
with a ruleset file named
.Pa default.rules
onto
.Pa /var/jail/dev .
.Bd -literal -offset indent
mount_devfs -o jail,ruleset=default.rules /var/jail/dev
.Ed
.Pp
A corresponding
.Xr fstab 5
entry is:
.Bd -literal -offset indent
devfs /var/jail/dev devfs ro,jail,ruleset=default.rules
.Ed
.Sh SEE ALSO
.Xr mount 2 ,
.Xr unmount 2 ,
.Xr devfs 5 ,
.Xr fstab 5 ,
.Xr devfsctl 8 ,
.Xr mount 8
.Sh HISTORY
The
.Nm
utility first appeared in
.Dx 2.3 .