[Chapter 45] 45.27 Turn Off echo for "Secret" Answers
Author: Jerry Peek, Tim O'Reilly & Mike Loukides
Date: 1998-08-04T21:54:59Z

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| Chapter 45 Shell Programming for the Initiated |

## 45.27 Turn Off echo for "Secret" Answers

When you type your password, UNIX turns off echoing so what you type won't show on the screen. You can do the same thing in shell scripts with `stty -echo`.

    stty

    read
    #!/bin/sh
       ...
    trap 'stty echo; exit' 0 1 2 3 15
    # use the right echo for your UNIX:
    echo "Enter code name: \c"
    #echo -n "Enter code name: "
    stty -echo
    read ans
    stty echo
       ...

The response is stored in `$ans`. The `trap` (44.12) helps to make sure that, if the user presses CTRL-c to abort the script, characters will be echoed again.

- JP

45.26 Quoted hereis Document Terminators: sh vs. csh |  | 45.28 Quick Reference: expr