wall --version (return code: 0)
wall from util-linux 2.27.1
wall --help (return code: 0)
Usage:
wall [options] [<file> | <message>]
Write a message to all users.
Options:
-n, --nobanner do not print banner, works only for root
-t, --timeout <timeout> write timeout in seconds
-h, --help display this help and exit
-V, --version output version information and exit
For more details see wall(1).