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WALL(1)                                                            User Commands                                                           WALL(1)

NAME
wall - write a message to all users SYNOPSIS
wall [-n] [-t timeout] [-g group] [message | file] DESCRIPTION
wall displays a message, or the contents of a file, or otherwise its standard input, on the terminals of all currently logged in users. The command will wrap lines that are longer than 79 characters. Short lines are whitespace padded to have 79 characters. The command will always put a carriage return and new line at the end of each line. Only the superuser can write on the terminals of users who have chosen to deny messages or are using a program which automatically denies messages. Reading from a file is refused when the invoker is not superuser and the program is set-user-ID or set-group-ID. OPTIONS
-n, --nobanner Suppress the banner. -t, --timeout timeout Abandon the write attempt to the terminals after timeout seconds. This timeout must be a positive integer. The default value is 300 seconds, which is a legacy from the time when people ran terminals over modem lines. -g, --group group Limit printing message to members of group defined as a group argument. The argument can be group name or GID. -V, --version Display version information and exit. -h, --help Display help text and exit. NOTES
Some sessions, such as wdm, that have in the beginning of utmp(5) ut_type data a ':' character will not get the message from wall. This is done to avoid write errors. SEE ALSO
mesg(1), talk(1), write(1), shutdown(8) HISTORY
A wall command appeared in Version 7 AT&T UNIX. AVAILABILITY
The wall command is part of the util-linux package and is available from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util- linux/>. util-linux August 2013 WALL(1)

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wall(1M)						  System Administration Commands						  wall(1M)

NAME
wall - write to all users SYNOPSIS
/usr/sbin/wall [-a] [-g grpname] [filename] DESCRIPTION
wall reads its standard input until an end-of-file. It then sends this message to all currently logged-in users preceded by: Broadcast Message from ... If filename is given, then the message is read in from that file. Normally, pseudo-terminals that do not correspond to rlogin sessions are ignored. Thus, when using a window system, the message appears only on the console window. However, -a will send the message even to such pseudo-terminals. It is used to warn all users, typically prior to shutting down the system. The sender must be superuser to override any protections the users may have invoked See mesg(1). wall runs setgid() to the group ID tty, in order to have write permissions on other user's terminals. See setuid(2). wall will detect non-printable characters before sending them to the user's terminal. Control characters will appear as a " ^ " followed by the appropriate ASCII character; characters with the high-order bit set will appear in "meta" notation. For example, `03' is dis- played as `^C' and `372' as `M-z'. OPTIONS
The following options are supported: -a Broadcast message to the console and pseudo-terminals. -g grpname Broadcast to the users in a specified group only, per the group database (see group(4)). ENVIRONMENT VARIABLES
If the LC_* variables (LC_CTYPE, LC_TIME, LC_COLLATE, LC_NUMERIC, and LC_MONETARY) are not set in the environment, the operational behav- ior of wall for each corresponding locale category is determined by the value of the LANG environment variable. See environ(5). If LC_ALL is set, its contents are used to override both the LANG and the other LC_* variables. If none of the above variables are set in the envi- ronment, the "C" (U.S. style) locale determines how wall behaves. FILES
/dev/tty* ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | |Availability |SUNWcsu | +-----------------------------+-----------------------------+ SEE ALSO
mesg(1), write(1), setuid(2), attributes(5), environ(5) NOTES
wall displays ``Cannot send to ...'' when the open on a user's tty file fails. SunOS 5.10 13 Jul 1994 wall(1M)

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