Invoke the keyboard as if it were a Script-file.
KEYBOARD invokes the keyboard as if it were a Script-file.
When placed in an M-file, KEYBOARD stops execution of the
file and gives control to the user's keyboard. The special
status is indicated by a double prompt. Variables may be
examined or changed - all MATLAB commands are valid. The
keyboard mode is terminated by executing the command RETURN
(i.e. typing the six letters R-E-T-U-R-N and pressing the
return key). Control returns to the invoking M-file.