trying to read with the -z/--null option makes the shell unresponsive #12624

-z / --null tells read to split on NUL bytes (\0) instead of newlines. So when you press Enter, read sees a newline, which is no longer its delimiter, and just keeps waiting for a NUL that never comes. Ctrl-C does not break out because read is blocked waiting on terminal input.

-z is meant for consuming NUL-separated data non-interactively, for example:

find . -type d -print0 | read -z dir

For an interactive prompt, just drop -z:

read -S -P "Please enter directory: " test_var

(If you ever genuinely need to end a NUL-delimited read from the keyboard, Ctrl-Space sends a NUL, but that is not what you want here.)