input_char [-noecho] “<prompt>” {<stuff>}
This command prompts the user to type ONE character and then runs the <stuff> and $* will be the user's response.
The -noecho option will suppress the outputting of the character to the input line as it is typed.
The $'…' expando is a wrapper around INPUT_CHAR in case you were wondering. It's always better to use INPUT_CHAR than $'…' if you can arrange it because it operates asynchronously, which means it plays nicely with other commands.
input_char "Press 'q' to quit, any other key to continue: " { unless ( [$0] == [q] ) { /* do whatever */ } }
The INPUT_CHAR command first appeared in EPIC3.003.