[vbezhenar]

apt-key could detect terminal output and modify its output.

[rlpb]

Writing any script would be hell if the commands you call suddenly start modifying their behaviour. This is bad practice, and the GNU coding standards (for example) agree: https://www.gnu.org/prep/standards/standards.html#User-Inter...

"Likewise, please don’t make the behavior of a command-line program depend on the type of output device it gets as standard output or standard input."

[icebraining]

Or just an extra flag like --list-after-import.