[SOLVED] reading password in a bash script

edwardcode · 08-17-2011, 12:39 PM

I am trying to write a script that will log in to all of the systems and change the password. I have the entire script written but the only problem is I use the "read" command in the script like so:

Code:

read -s PASSWORD

the only problem is that when I use the "PASSWORD" variable later on in the script it will not put in the password correctly because there are symbols in my password. Such as "$" and it will then think that everything after that symbol is a variable. Is there some way to force it to not do anything with the symbols in my password.

below you will see the script I am a tempting to change my passwd. Assume that the variables are correct.:

Code:

echo -n "Please type your current password: "
read -s OLDPASSWD
echo ""
echo -n "Please type your new password: "
read -s NEWPASSWD
echo ""

 for SERVER in ${softwareforge}; do
   /usr/bin/expect << EOF
        spawn ssh -t ${USERNAME}@${SERVER}
        expect "*?assword: "
        send "${CURRENTPASSWD=}\n"
        expect "*]$ "
        send "passwd\n"
        expect "*?assword: "
        send "${OLDPASSWD}\n"
        expect "*?assword: "
        send "${NEWPASSWD}\n"
        expect "*?assword: "
        send "${NEWPASSWD}\n"
EOF

done

ta0kira · 08-17-2011, 01:06 PM

Maybe you can pass the strings to expect in hex?

Code:

        send "$( echo -n "$OLDPASSWD" | od -An -vtx1 | tr -d '\n' | sed 's/ /\\x/g' )\n"

Kevin Barry

edwardcode · 08-17-2011, 01:32 PM

I worked! Just so I can understand what is going on can you explain this command to m?

Thanks

ta0kira · 08-17-2011, 01:53 PM

od is a utility for converting data to other forms; normally it will show groupings of octal numbers and index the ouput lines. The options -An -vtx1 (actually -A, -v, and -t, where n goes with -A and x1 goes with -t) are what's necessary for od to print everything in hex pairs corresponding to each byte. The call to tr removes the newlines added for formatting by od and the call to sed prepends "\x" to each hex pair so expect can understand that it's hex. The -n with echo makes sure it doesn't output a newline, although you could take out -n and also "\n" from the "send" line and it would work the same. To see each step of the process, start with the echo ... | od ... on the command line, then add in tr, then sed.
Kevin Barry

edwardcode · 08-17-2011, 02:32 PM

Dude you are awesome. Thanks for the lesson and the help with the command.