Prints a "🚫" character and adds a newline if the cursor is not in column 1.
You can use it in your shell prompt to tidy up after commands that output some
text without a trailing newline.
![Example terminal session showing the problem of an unterminated command mixing with the shell prompt, and then the program correctly detecting the presence or absence of a non-newline-terminated output and using the "🚫" character appropriately.](example.gif)
You can install this into your `~/.bashrc`, for example: