119 lines
3.8 KiB
Groff
119 lines
3.8 KiB
Groff
.\" Copyright (c) 1987, 1990, 1993
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.\" The Regents of the University of California. All rights reserved.
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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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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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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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.\" @(#)mesg.1 8.1 (Berkeley) 6/6/93
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.\"
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.TH MESG 1 "July 2014" "util-linux" "User Commands"
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.SH NAME
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mesg \- display (or do not display) messages from other users
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.SH SYNOPSIS
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.B mesg
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[option]
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.RB [ n | y ]
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.SH DESCRIPTION
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The
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.B mesg
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utility is invoked by a user to control write access others have to the
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terminal device associated with standard error output. If write access
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is allowed, then programs such as
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.BR talk (1)
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and
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.BR write (1)
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may display messages on the terminal.
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.PP
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Traditionally, write access is allowed by default. However, as users
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become more conscious of various security risks, there is a trend to remove
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write access by default, at least for the primary login shell. To make
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sure your ttys are set the way you want them to be set,
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.B mesg
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should be executed in your login scripts.
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.PP
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The
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.B mesg
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utility silently exits with error status 2 if not executed on terminal. In this
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case execute
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.B mesg
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is pointless. The command line option \fB\-\-verbose\fR forces
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mesg to print a warning in this situation. This behaviour has been introduced
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in version 2.33.
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.SH ARGUMENTS
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.TP
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.B n
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Disallow messages.
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.TP
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.B y
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Allow messages to be displayed.
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.PP
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If no arguments are given,
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.B mesg
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shows the current message status on standard error output.
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.SH OPTIONS
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.TP
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.BR \-v , " \-\-verbose"
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Explain what is being done.
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.TP
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.BR \-V , " \-\-version"
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Display version information and exit.
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.TP
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.BR \-h , " \-\-help"
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Display help text and exit.
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.SH EXIT STATUS
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The
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.B mesg
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utility exits with one of the following values:
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.RS 4
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.TP
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.B "\ 0"
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Messages are allowed.
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.TP
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.B "\ 1"
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Messages are not allowed.
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.TP
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.B ">1"
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An error has occurred.
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.RE
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.SH FILES
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.I /dev/[pt]ty[pq]?
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.SH "SEE ALSO"
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.BR login (1),
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.BR talk (1),
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.BR write (1),
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.BR wall (1),
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.BR xterm (1)
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.SH HISTORY
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A
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.B mesg
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command appeared in Version 6 AT&T UNIX.
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.SH AVAILABILITY
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The mesg command is part of the util-linux package and is available from
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https://www.kernel.org/pub/linux/utils/util-linux/.
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