5f2edd80fc
Just like the old TTY layer, the current MPSAFE TTY layer does not make any attempt to serialize calls of write(). Data is copied into the kernel in 256 (TTY_STACKBUF) byte chunks. If a write() call occurs at the same time, the data may interleave. This is especially likely when the TTY starts blocking, because the output queue reaches the high watermark. I've implemented this by adding a new flag, TTY_BUSY_OUT, which is used to mark a TTY as having a thread stuck in write(). Because I don't want non-blocking processes to be possibly blocked by a sleeping thread, I'm still allowing it to bypass the protection. According to this message, the Linux kernel returns EAGAIN in such cases, but I think that's a little too restrictive: http://kerneltrap.org/index.php?q=mailarchive/linux-kernel/2007/5/2/85418/thread PR: kern/118287
252 lines
6.4 KiB
Groff
252 lines
6.4 KiB
Groff
.\" Copyright (c) 1980, 1991, 1993, 1994
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.\" The Regents of the University of California. All rights reserved.
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.\" Copyright (c) 2002 Networks Associates Technology, Inc.
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.\" All rights reserved.
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.\"
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.\" Portions of this software was developed for the FreeBSD Project by
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.\" ThinkSec AS and NAI Labs, the Security Research Division of Network
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.\" Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
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.\" ("CBOSS"), as part of the DARPA CHATS research program.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)pstat.8 8.5 (Berkeley) 5/13/94
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.\" $FreeBSD$
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.\"
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.Dd August 20, 2008
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.Dt PSTAT 8
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.Os
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.Sh NAME
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.Nm pstat ,
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.Nm swapinfo
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.Nd display system data structures
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.Sh SYNOPSIS
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.Nm
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.Op Fl Tfghkmnst
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.Op Fl M Ar core Op Fl N Ar system
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.Nm swapinfo
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.Op Fl ghkm
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.Op Fl M Ar core Op Fl N Ar system
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.Sh DESCRIPTION
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The
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.Nm
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utility displays open file entry, swap space utilization,
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terminal state, and vnode data structures.
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.Pp
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If invoked as
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.Nm swapinfo
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the
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.Fl s
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option is implied, and only the
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.Fl k , m , g ,
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and
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.Fl h
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options are legal.
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.Pp
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If the
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.Fl M
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option is not specified, information is obtained from
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the currently running kernel via the
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.Xr sysctl 3
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interface.
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Otherwise, information is read from the specified core file,
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using the name list from the specified kernel image (or from
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the default image).
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.Pp
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The following options are available:
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.Bl -tag -width indent
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.It Fl n
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Print devices out by major/minor instead of name.
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.It Fl h
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.Dq Human-readable
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output.
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Use unit suffixes when printing swap partition sizes:
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Byte, Kilobyte, Megabyte, Gigabyte, Terabyte and Petabyte.
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.It Fl k
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Print sizes in kilobytes, regardless of the setting of the
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.Ev BLOCKSIZE
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environment variable.
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.It Fl m
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Print sizes in megabytes, regardless of the setting of the
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.Ev BLOCKSIZE
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environment variable.
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.It Fl g
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Print sizes in gigabytes, regardless of the setting of the
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.Ev BLOCKSIZE
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environment variable.
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.It Fl T
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Print the number of used and free slots in several system tables.
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This is useful for checking to see how large system tables have become
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if the system is under heavy load.
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.It Fl f
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Print the open file table with these headings:
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.Bl -tag -width indent
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.It LOC
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The core location of this table entry.
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.It TYPE
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The type of object the file table entry points to.
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.It FLG
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Miscellaneous state variables encoded thus:
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.Pp
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.Bl -tag -width indent -compact
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.It R
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open for reading
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.It W
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open for writing
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.It A
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open for appending
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.It I
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signal pgrp when data ready
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.El
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.It CNT
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Number of processes that know this open file.
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.It MSG
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Number of messages outstanding for this file.
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.It DATA
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The location of the vnode table entry or socket structure for this file.
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.It OFFSET
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The file offset (see
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.Xr lseek 2 ) .
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.El
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.It Fl s
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Print information about swap space usage on all the
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swap areas compiled into the kernel.
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The first column is the device name of the partition.
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The next column is
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the total space available in the partition.
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The
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.Ar Used
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column indicates the total blocks used so far; the
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.Ar Available
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column indicates how much space is remaining on each partition.
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The
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.Ar Capacity
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reports the percentage of space used.
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.Pp
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If more than one partition is configured into the system, totals for all
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of the statistics will be reported in the final line of the report.
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.It Fl t
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Print table for terminals
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with these headings:
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.Bl -tag -width indent
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.It LINE
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Device name.
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.It INQ
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Number of characters that can be stored in the input queue.
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.It CAN
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Number of characters in the input queue which can be read.
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.It LIN
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Number of characters in the input queue which cannot be read yet.
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.It LOW
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Low water mark for input.
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.It OUTQ
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Number of characters that can be stored in the output queue.
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.It USE
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Number of bytes in the output queue.
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.It LOW
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Low water mark for output.
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.It COL
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Calculated column position of terminal.
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.It SESS
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Kernel address of the session structure.
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.It PGID
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Process group for which this is the controlling terminal.
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.It STATE
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Miscellaneous state variables encoded thus:
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.Pp
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.Bl -tag -width indent -compact
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.It I
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init/lock-state device nodes present
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.It C
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callout device nodes present
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.It O
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opened
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.It c
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console in use
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.It G
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gone
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.It B
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busy in
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.Xr open 2
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.It Y
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send SIGIO for input events
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.It L
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next character is literal
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.It H
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high watermark reached
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.It X
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open for exclusive use
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.It S
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output stopped (ixon flow control)
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.It l
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block mode input routine in use
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.It Z
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connection lost
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.It s
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i/o being snooped
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.It b
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busy in
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.Xr read 2
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or
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.Xr write 2
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.El
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.Pp
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The
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.Ql i
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and
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.Ql o
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characters refer to the previous character, to differentiate between
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input and output.
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.El
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.It Fl M
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Extract values associated with the name list from the specified core.
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.It Fl N
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If
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.Fl M
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is also specified,
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extract the name list from the specified system instead of the default,
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which is the kernel image the system has booted from.
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.El
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.Sh SEE ALSO
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.Xr ps 1 ,
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.Xr systat 1 ,
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.Xr stat 2 ,
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.Xr fs 5 ,
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.Xr iostat 8 ,
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.Xr vmstat 8
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.Rs
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.%T UNIX Implementation
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.%A K. Thompson
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.Re
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.Sh HISTORY
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The
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.Nm
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utility appeared in
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.Bx 4.0 .
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.Sh BUGS
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Does not understand
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.Tn NFS
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swap servers.
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