1.\" 2.\" Copyright (c) 2008 Daniel Gerzo 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS DOCUMENTATION IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24.\" 25.\" $FreeBSD: src/share/man/man5/nullfs.5,v 1.1 2008/10/05 18:57:27 danger Exp $ 26.\" 27.Dd March 20, 2010 28.Dt NULL 5 29.Os 30.Sh NAME 31.Nm nullfs 32.Nd "null file system" 33.Sh SYNOPSIS 34To enable support for 35.Nm , 36place the following line in the kernel configuration file: 37.Bd -ragged -offset indent 38.Cd "options NULLFS" 39.Ed 40.Pp 41Alternatively, to load the driver as a 42module at boot time, place the following line in 43.Xr loader.conf 5 : 44.Bd -literal -offset indent 45null_load="YES" 46.Ed 47.Sh DESCRIPTION 48The 49.Nm 50driver will permit the 51.Dx 52kernel to mount a loopback file system sub-tree. 53.Sh EXAMPLES 54To mount a 55.Nm 56file system: 57.Pp 58.Dl "mount_null /usr/src /home/devel/src" 59.Sh SEE ALSO 60.Xr fstab 5 , 61.Xr mount_null 8 62.Sh HISTORY 63The 64.Nm 65layer first appeared in 66.Bx 4.4 . 67.Sh AUTHORS 68.An -nosplit 69The 70.Nm 71kernel implementation was written by 72.An John Heideman . 73.Pp 74This manual page was written by 75.An Daniel Gerzo Aq danger@FreeBSD.org . 76