wall - write to all users wall
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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. Nor- mally, 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 sys- tem. 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 permis- sions 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, `\003' is displayed 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 behavior 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 environ- ment, 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 system/core-os | +-----------------------------------------------------------+ 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 5.11 23 Feb 2015 wall(1M)
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