254 lines
4.3 KiB
Plaintext
254 lines
4.3 KiB
Plaintext
.TH CONSOLEFS 4
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.SH NAME
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consolefs, C, clog \- file system for console access
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.SH SYNOPSIS
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.B aux/consolefs
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[
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.B -m
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.I mntpt
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] [
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.B -c
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.I consoledb
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]
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.PP
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.B C
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.I system
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.PP
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.B aux/clog
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console log
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.I system
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.SH DESCRIPTION
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To ease administration of multiple machines one might attach
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many serial console lines to a single computer.
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.I Consolefs
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is a file system that lets multiple users simultaneously access
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these console lines.
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The consoles and permissions to access them are defined in the
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file
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.I consoledb
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(default
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.BR /lib/ndb/consoledb ).
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The format of
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.I consoledb
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is the same as that of other
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.B /lib/ndb
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files,
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.IR ndb (6).
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Consoles are defined by entries of the form:
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.PP
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.EX
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console=dirty dev=/dev/eia205
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uid=bignose
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gid=support
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speed=56200
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cronly=
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.EE
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.PP
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Each
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.IR console / dev
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pair represents the name of a console and the device
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associated with it.
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.I Consolefs
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presents a single level directory with up to three files
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per console:
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.IR console ,
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.IB console ctl\f1,
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and
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.IB console stat\f1.
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Writes of
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.I console
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are equivalent to writes of
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.I dev
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and reads and writes of
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.IB console ctl
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and
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.IB console stat
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are equivalent to reads and writes of
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.IB dev ctl
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and
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.IB dev stat
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respectively.
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.IB Console ctl
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and
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.IB console stat
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will not exist if the underlying
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.I dev
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does not provide them.
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.I Consolefs
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broadcasts anything it reads from
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.I dev
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to all readers of
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.IR console .
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Therefore, many users can
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.IR con (1)
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to a
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.IR console ,
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see all output, and enter commands.
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.PP
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The
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.I cronly=
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attribute causes newlines typed by the user to be sent to
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the console as returns.
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The
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.I speed=x
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attribute/value pair specifies a bit rate for the
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console. The default is 9600 baud.
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The
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.I openondemand=
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attribute causes the console device
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.RI ( dev )
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to be opened only when the corresponding
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.IB mntpt / console
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file is open.
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.PP
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Access to the console is controlled by the
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.I uid
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and
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.I gid
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attributes/value pairs.
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The uid values are user account names.
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The gid values are the names of groups defined in
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.I consolefs
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by entries of the form:
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.PP
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.EX
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group=support
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uid=bob
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uid=carol
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uid=ted
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uid=alice
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.EE
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.PP
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Groups are used to avoid excessive typing. Using
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.I gid=x
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is equivalent to including a
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.I uid=y
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for each user
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.I y
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that is a member of
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.IR x .
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.PP
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To keep users from inadvertently interfering with one another,
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notification is broadcast to all readers whenever a user
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opens or closes
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.IR name .
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For example, if user
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.B boris
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opens a console that users
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.B vlad
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and
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.B barney
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have already opened, all will read the message:
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.PP
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.EX
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[+boris, vlad, barney]
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.EE
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.PP
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If
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.B vlad
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then closes,
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.B boris
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and
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.B barney
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will read:
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.PP
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.EX
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[-vlad, boris, barney]
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.EE
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.PP
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.I Consolefs
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posts the client end of its 9P channel in
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.BR /srv/consolefs
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and mounts this locally in
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.I mntpt
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(default
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.BR /mnt/consoles );
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remote clients must
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.B mount
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(see
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.IR bind (1))
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this file to see the consoles.
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.PP
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The
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.IR rc (1)
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script
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.B C
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automates this procedure.
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It uses
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.IR import (4)
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to connect to
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.B /mnt/consoles
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on the machine connected to all the consoles, then uses
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.IR con (1)
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to connect to the console of the machine
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.IR system.
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The script must be edited at installation
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by the local administration to identify the
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system that holds
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.BR /mnt/consoles .
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.PP
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.I Aux/clog
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opens the file
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.I console
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and writes every line read from it, prefixed
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by the ASCII time to the file
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.IR log .
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.PP
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An example of 2 consoles complete with console logging is:
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.IP
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.EX
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% cat /lib/ndb/consoledb
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group=sys
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uid=glenda
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console=bootes dev=/dev/eia0 gid=sys
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console=fornax dev=/dev/eia1 gid=sys
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% aux/consolefs
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% ls -p /mnt/consoles
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bootes
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bootesctl
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fornax
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fornaxctl
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% clog /mnt/consoles/fornax /sys/log/fornax &
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% clog /mnt/consoles/bootes /sys/log/bootes &
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.EE
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.PP
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The console server's default name space must
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mount the consoles for
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.I C
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to import.
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This can be arranged by adding
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.IP
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.EX
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mount /srv/consoles /mnt/consoles
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.EE
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.LP
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to
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.BR /lib/namespace.$sysname .
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.SH FILES
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.TF /lib/ndb/consoledb
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.TP
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.B /srv/consoles
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Client end of pipe to server.
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.TP
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.B /mnt/consoles
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Default mount point.
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.TP
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.B /lib/ndb/consoledb
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Default user database.
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.SH SOURCE
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.B /sys/src/cmd/aux/consolefs.c
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.br
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.B /rc/bin/C
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.br
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.B /sys/src/cmd/aux/clog.c
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.SH BUGS
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.PP
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Changing the gid's or uid's while
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.I consolefs
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is running
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is detected by
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.IR consolefs .
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However, to add new consoles
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one must restart
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.IR consolefs .
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