Linux: How to send message to local user logged into X11?

Question

Is possible to send a message (popup window or something) to local user logged into X (xdm, fluxbox) from console ? For example: user1 is logged and using X/fluxbox, user2 logging into the same box by ssh to console. Now - what user2 have to do to send message to user1 ?

Answer 1

The xmessage tool lets you do exactly that; present a popup window to users with a text message inside.

Example: user2 logs into a BASH session on the box and issues:

export DISPLAY=':0.0'
xmessage "some message here"

if you log into a TSCH session, it'd be something like this:

setenv DISPLAY ':0.0'
xmessage "some message here'

Alternatively, you can send messages to terminal sessions in one of two ways:

Using wall (=warn all [users])

From the man page:
Wall displays the contents of file or, by default, its standard input, on the terminals of all currently logged in users.

If you want to target a specific user, use write. Again, man tells us:

The write utility allows you to communicate with other users, by copying lines from your terminal to theirs.