topic Re: How to hide password using shell script in Operating System - HP-UX

How to hide password using shell script

Catherine_3 — Fri, 12 Apr 2002 16:09:58 GMT

Hi everyone,
I met a problem
I have a shell script:

echo " input Host name "
read HOST
echo "input User Name "
read USERID
echo " input Password"
read PASSWD

ftp -n -i $HOST <<- EOF
user $USERID $PASSWD
..
..
EOF

I want to hide my password and don't appear on
the screen.

Thanks a lot

Re: How to hide password using shell script

A. Clay Stephenson — Fri, 12 Apr 2002 16:15:23 GMT

#!/usr/bin/sh

trap 'stty echo; exit' 0 1 2 3 15

echo "Enter Password: \c"
stty -echo
read PASSWD
stty echo

I should add that the trap command is really not optional. You see, the stty command alters the tty device not just your script. Any subsequent processes would also have the echo turned off if you exited in the -echo state. The trap, insure that the terminal is restored upon exit even via a Ctrl-C (or whatever your n'rupt is set to).

I suggest that you comment out the trap statement and do a ctrl-c when entering the password and you will see just what I mean.

Regards, Clay

Re: How to hide password using shell script

S.K. Chan — Fri, 12 Apr 2002 16:15:39 GMT

You would put ..

stty -echo

before the "read password" part
and

stty echo

after that.

Re: How to hide password using shell script

Catherine_3 — Fri, 12 Apr 2002 16:44:38 GMT

Hi clay,

I had a test. You are right.

thanks clay and chan

Re: How to hide password using shell script

Catherine_3 — Fri, 12 Apr 2002 16:47:08 GMT

Hi

By the way, I just want to make the cursor move and display "******"
so How to do that ?

Re: How to hide password using shell script

A. Clay Stephenson — Fri, 12 Apr 2002 17:56:02 GMT

That is much more difficult because you have to turn off line-buffered entry and enable character by character input. That is something generally not done from the shell.
You can use the command 'tput cup row column' to position the cursor. Man tput, terminfo for details.

Re: How to hide password using shell script

Catherine_3 — Fri, 12 Apr 2002 19:12:55 GMT

Thanks a lot Clay