WALL(1) User Commands WALL(1)
wall – write a message to all users
wall [-n] [-t timeout] [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 mes‐
Reading from a file is refused when the invoker is not superuser and
the program is suid or sgid.
Suppress the banner.
-t, –timeout timeout
Abandon the write attempt to the terminals after timeout sec‐
onds. This timeout must be a positive integer. The default
value is 300 seconds, which is a legacy from the time when peo‐
ple ran terminals over modem lines.
Display version information and exit.
Display help text and exit.
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.
A wall command appeared in Version 7 AT&T UNIX.
The wall command is part of the util-linux package and is available
from Linux Kernel Archive ⟨ftp://ftp.kernel.org/pub/linux/utils/util-
util-linux August 2013 WALL(1)
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