Password characters 2

[scriptfinder]

Please someone help me find a way to solve password character issue.
I have 2 input statements for the user, one of which is a password to be entered. When the user inputs the password on the screen, I would like the characters to appear as asterisks or stars. I can use stty to make the characters disappear but I was wondering if I can print some special characters instead of blanks.
Thank you in advance and you guys really rock!

 

[Annihilannic]

That isn't straightforward. What shell and OS are you using?

In bash you could put a while loop around read -n1 commands to read each individual character and display an appropriate character on screen, but you would have to handle cursor positioning manually for backspacing, etc.

Annihilannic.

 

[scriptfinder]

Sorry for getting back to you late and thanks for the response.
The OS is SunOs and the shell is ksh.
BTW, read -n1 came out as a bad option error.

In a nutshell, the user should be able to see some characters while entering the password. The user is going to run a very long script in which entering a password is in the middle and if the user fails to enter the right password, the process has to be started all the way from the beginning. I know that wrong password will result in rerun but if I can at least help the user see some chars being entered I can avoid a possible rerun of the script.

Your help is appreciated.

 

[olded]

It's not particularly pretty, but this code snippet seems to do it. Let me know if you have any questions.

#!/bin/ksh

readkey() {
oldstty=`stty -g`
stty -icanon -echo min 1 time 0
dd bs=1 count=1 <&0 2>/dev/null
stty $oldstty
}

row=10
col=17
tput clear
tput cup $row 1
echo "Enter Password:"
tput cup $row $col
while true
do
   mychar=$(readkey)
   # break for the CR key
   if [[ -z $mychar ]]
   then
      break
   fi
   echo "*\c"
   mypassword="$mypassword"$mychar
done
((row+=11))
tput cup $row 10
echo $mypassword

 

[Annihilannic]

Nice work Ed. Here are some modifications to handle backspacing, note that the backspace character is hard-coded though and must be entered in vi using "Ctrl-V, Backspace":

#!/bin/ksh

readkey() {
oldstty=`stty -g`
stty -icanon -echo min 1 time 0
dd bs=1 count=1 <&0 2>/dev/null
stty $oldstty
}

row=10
col=17
tput clear
tput cup $row 1
echo "Enter Password:"
tput cup $row $col
while true
do
   mychar=$(readkey)
   # break for the CR key
   if [[ -z $mychar ]]
   then
      break
   fi
   if [[ "$mychar" = "^?" && ${#mypassword} -gt 0 ]]
   then
      tput cub1 ; echo " \c" ; tput cub1
      mypassword="${mypassword%?}"
   else
      echo "*\c"
      mypassword="$mypassword"$mychar
   fi
done
((row+=11))
tput cup $row 10
echo $mypassword

Annihilannic.

 

[Annihilannic]

Correction for correct handling of backspace at the beginning of the field:

...
   if [[ "$mychar" = " ]]
   then
      if [[ ${#mypassword} -gt 0 ]]
      then
         tput cub1 ; echo " \c" ; tput cub1
         mypassword="${mypassword%?}"
      fi
...

Annihilannic.

 

[scriptfinder]

You guys are great! it works fine except that backspaces appear as chars and the spacebar acts as backspace. Shouldn't it be the other way? Any ideas?

Also, I just made one minor correction - a closing double quote after "$mychar" = " ". Am I right?

 

[olded]

Thanks, Annihilannic. Good hearing from you.

Those pesky special characters always get in the way. It's really a case of how your keyboards are mapped.

 

[Annihilannic]

scriptfinder, if you do an stty -a what is shown as the "erase" character?

When you entered or copied/pasted the script, did you use Ctrl-V, backspace for the "^?" part instead of just typing a "^" and a "?"?

Annihilannic.

 

[scriptfinder]

I just now did what you mentioned and no issues now.

You guys are too good!

 

[hokky]

Hi guys,

what this doesn't work in linux :

The result it :

Enter Password: stty: standard input: Bad file descriptor
*stty: standard input: Bad file descriptor
*stty: standard input: Bad file descriptor
*stty: standard input: Bad file descriptor
*stty: standard input: Bad file descriptor
*stty: standard input: Bad file descriptor
*stty: standard input: Bad file descriptor
*stty: standard input: Bad file descriptor

haitest

why they keep complaining about "Bad file descriptor" ?

 

[Annihilannic]

Works fine for me on RHEL AS2.1, AS 3.0 and SLES9. What version of ksh or pdksh are you using?

Annihilannic.