This page provides commands that can be used to produce a graphical popup and to broadcast a message to opened terminals.

It also indicates how to setup reminders by having these commands called periodically by cron.

Graphical popup (using xmessage)

The xmessage command (provided by package x11-utils on a Debian GNU/Linux system) causes a popup message box to appear:

xmessage 'My message'

xmessage -display :0.0 'My message'            # A cron job launching
                                               # xmessage with the display
                                               # option fails.

xmessage -center -geometry 130x68 'My message' # Specifies position (center
                                               # of the screen) and size.
                                               # In Xmonad at least, message
                                               # is not readable if size is
                                               # not specified.

Follow the link for more information about X applications command line options.

Broadcasted message (using wall)

The wall command (provided by package bsdutils on a Debian GNU/Linux system) causes a message to be broadcasted to every terminal:

wall 'My message'

Using cron to display or broadcast a message

Add a job to your crontab with:

crontab -e

List the content of your crontab with:

crontab -l

An example output of "crontab -l" (with a xmessage job) is downloadable.