freebsd-dev/share/man/man5/devfs.5
Glen Barber ea46a1350c Fix '.Xr' ordering in SEE ALSO section.
Approved by:	keramida (mentor)
MFC after:	3 days
2011-01-22 13:18:28 +00:00

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.Dd September 18, 2010
.Dt DEVFS 5
.Os
.Sh NAME
.Nm devfs
.Nd device file system
.Sh SYNOPSIS
.Bd -literal
devfs /dev devfs rw 0 0
.Ed
.Sh DESCRIPTION
The device file system, or
.Nm ,
provides access to kernel's device
namespace in the global file system namespace.
The conventional mount point is
.Pa /dev .
.Pp
The file system includes several directories, links, symbolic links
and devices, some of which can also be written.
In a chroot'ed
environment,
.Nm
can be used to create a new
.Pa /dev
mount point.
.Pp
The
.Xr mknod 8
tool can be used to recover deleted device entries under
.Nm .
.Pp
The
.Xr fdescfs 5
filesystem is an alternate means for populating
.Pa /dev/fd .
The character devices that both
.Nm
and
.Xr fdescfs 5
present in
.Pa /dev/fd
correspond to the open file descriptors of the process
accessing the directory.
.Nm
only creates files for the standard file descriptors
.Pa 0 ,
.Pa 1
and
.Pa 2 .
.Xr fdescfs 5
creates files for all open descriptors.
.Sh FILES
.Bl -tag -width /dev/XXXX -compact
.It Pa /dev
The normal
.Nm
mount point.
.El
.Sh EXAMPLES
To mount a
.Nm
volume located on
.Pa /mychroot/dev :
.Pp
.Dl "mount -t devfs devfs /mychroot/dev"
.Sh SEE ALSO
.Xr fdescfs 5 ,
.Xr devfs 8 ,
.Xr mount 8
.Sh HISTORY
The
.Nm
file system first appeared in
.Fx 2.0 .
It became the preferred method for accessing devices in
.Fx 5.0
and the only method in
.Fx 6.0 .
The
.Nm
manual page first appeared in
.Fx 2.2 .
.Sh AUTHORS
The
.Nm
manual page was written by
.An Mike Pritchard Aq mpp@FreeBSD.org .