wall - write a message to all users
wall [-n] [-t
timeout] [-g group] [message
| file]
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.
-n, --nobanner
Suppress the banner.
-t, --timeout timeout
Abandon the write attempt to the terminals after
timeoutseconds. Thistimeoutmust 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
groupargument. The argument can be group name or GID.
-h, --help
Display help text and exit.
-V, --version
Print version and exit.
Some sessions, such as wdm(1x), 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.
A wall command appeared in Version 7 AT&T UNIX.
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.
The wall command is part of the util-linux package
which can be downloaded from Linux Kernel Archive
<https://www.kernel.org/pub/linux/utils/util-linux/>.