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@(#)mount_kernfs.8 8.2 (Berkeley) 3/27/94
.Dd March 22, 2012 .Dt MOUNT_KERNFS 8 .Os .Sh NAME .Nm mount_kernfs .Nd mount the /kern file system .Sh SYNOPSIS .Nm .Op Fl o Ar options .Ar /kern .Ar mount_point .Sh DESCRIPTION The .Nm command attaches an instance of the kernel parameter namespace to the global filesystem namespace. The conventional mount point is
a /kern . The directory specified by .Ar mount_point is converted to an absolute path before use. This command is normally executed by .Xr mount 8 at boot time.
p The filesystem includes several regular files which can be read, some of which can also be written. The contents of the files is in a machine-independent format, either a string, or an integer in decimal ASCII. Where numbers are returned, a trailing newline character is also added.
p The options are as follows: l -tag -width indent t Fl o Options are specified with a .Fl o flag followed by a comma separated string of options. See the .Xr mount 8 man page for possible options and their meanings. .El .Sh FILES l -tag -width copyright -compact t Pa boottime the time at which the system was last booted (decimal ASCII). t Pa copyright kernel copyright message. t Pa hostname the hostname, with a trailing newline. The hostname can be changed by writing to this file. A trailing newline will be stripped from the hostname being written. t Pa hz the frequency of the system clock (decimal ASCII). t Pa loadavg the 1, 5 and 15 minute load average in kernel fixed-point format. The final integer is the fix-point scaling factor. All numbers are in decimal ASCII. t Pa msgbuf the kernel message buffer, also read by .Xr syslogd 8 , through the
a log
device, and by
.Xr dmesg 8 .
t Pa pagesize the machine pagesize (decimal ASCII).
t Pa physmem the number of pages of physical memory in the machine (decimal ASCII).
.It Pa root
the system root directory.
In a chroot'ed environment,
.Nm
can be used to create a new
.Pa /kern
mount point.
.Pa /kern/root
will then refer to the system global root, not the current process root.
t Pa rootdev the root device.
t Pa rrootdev the raw root device.
t Pa time the second and microsecond value of the system clock.
Both numbers are in decimal ASCII.
t Pa version the kernel version string.
The head line for
a /etc/motd can be generated by running: .Dq Ic "sed 1q /kern/version" .El .Sh SEE ALSO .Xr mount 2 , .Xr unmount 2 , .Xr fstab 5 , .Xr dmesg 8 , .Xr mount 8 , .Xr setkey 8 , .Xr syslogd 8 .Sh HISTORY The .Nm utility first appeared in x 4.4 . .Sh BUGS This filesystem may not be NFS-exported.
Indexes created Tue Sep 23 13:09:54 GMT 2025