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wall(1m) [sunos man page]

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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SHUTDOWN(8)							     shutdown							       SHUTDOWN(8)

NAME
shutdown - Halt, power-off or reboot the machine SYNOPSIS
shutdown [OPTIONS...] [TIME] [WALL...] DESCRIPTION
shutdown may be used to halt, power-off or reboot the machine. The first argument may be a time string (which is usually "now"). Optionally, this may be followed by a wall message to be sent to all logged-in users before going down. The time string may either be in the format "hh:mm" for hour/minutes specifying the time to execute the shutdown at, specified in 24h clock format. Alternatively it may be in the syntax "+m" referring to the specified number of minutes m from now. "now" is an alias for "+0", i.e. for triggering an immediate shutdown. If no time argument is specified, "+1" is implied. Note that to specify a wall message you must specify a time argument, too. If the time argument is used, 5 minutes before the system goes down the /run/nologin file is created to ensure that further logins shall not be allowed. OPTIONS
The following options are understood: --help Prints a short help text and exits. -H, --halt Halt the machine. -P, --poweroff Power-off the machine (the default). -r, --reboot Reboot the machine. -h Equivalent to --poweroff, unless --halt is specified. -k Do not halt, power-off, reboot, just write wall message. --no-wall Do not send wall message before halt, power-off, reboot. -c Cancel a pending shutdown. This may be used cancel the effect of an invocation of shutdown with a time argument that is not "+0" or "now". EXIT STATUS
On success, 0 is returned, a non-zero failure code otherwise. SEE ALSO
systemd(1), systemctl(1), halt(8), wall(1) systemd 208 SHUTDOWN(8)
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