Shell Programming and Scripting

#! /usr/bin/ksh

exec 4>/dev/tty

function getpass
{
        typeset prompt=$1
        typeset backspace=$(echo  \\b\\c)
        typeset enter=$(echo \\r\\c)
        typeset savesetting=$(stty -g)
        typeset keystroke password n i reading result
        n=0
        echo "${prompt}"\\c >&4
        stty -echo -icrnl -icanon min 1 time 0
        reading=1
        while ((reading)) ; do
                keystroke=$(dd bs=1 count=1 2>/dev/null)
                case $keystroke in
                $enter)
                        reading=0
                        ;;
                $backspace)
                        if ((n)) ; then
                                echo "${backspace} ${backspace}"\\c >&4
                                ((n=n-1))
                        fi
                        ;;
                *)
                        echo \*\\c >&4
                        data[n]=$keystroke
                        ((n=n+1))
                esac
        done
        stty "$savesetting"
        echo >&4
        result=""
        i=0
        while  ((i<n)) ; do
                result="${result}${data[i]}"
                ((i=i+1))
        done
        echo $result
        return 0
}

final=$(getpass "password -  ")
echo the password is $final
exit 0