cros-motd provides a way to present Crostini users with a textual message printed into the Terminal app (or any other terminal emulator launching a “login” shell in the Crostini container) upon startup.
The message is defined in the same script (cros-motd.sh) that contains the presentation logic and will only be presented a limited number of times before silencing itself. It also offers the user a way to silence it earlier by executing a short shell command snippet appended to the message.
The cros-motd concept is delivered as a versioned Debian package, to be automatically installed into the Crostini container for both existing and new environments upon a ChromeOS release update.
To specify the number of presentations before the message silences itself, set the difference between the COUNTER_MAX and COUNTER_INITIAL constants in the cros-motd.sh file accordingly.
To update the message and ensure that it will be shown for users that have already seen and silenced a previous message, increment the package version in the deb-description file, update the COUNTER_INITIAL and COUNTER_MAX constants such that they are both greater-than or equal to the previous version's COUNTER_MAX, rebuild the package, and ensure it is included in the next container uprev.