Entering Password in su- through loop

Question

The Scenario is like I have a list of root passwords. But i don't want to keep trying Manually. So i wrote the shell script :

for i in {1..26}

do

su - >>result

done

and all my password are on a file "attempt.txt".

Now on Command Prompt i type the Command :

bash p2.sh < attempt.txt

But It shows errors : "Standard in must be a tty"

So is there some way I can enter these passwords through some codes or commands without manually typing each Of those? Please tell a command-line approach instead of some advanced utility software. I'm in it for learning. Thanks :)

Answer 1

The correct syntax is this:

 while read my_pass
 do 
        echo $my_pass | sudo -S command
 done < file_name

Three comments: you cannot use su inside a script file, you will need to use sudo with the -S option which, according to the man,

The -S (stdin) option causes sudo to read the password from the standard input instead of the terminal device.

Second, if you do not like to write the file_name inside the script, use one of the $n arguments, like $1 if it is the only parameter passed.

Third, are you sure collecting all of your passwords in a single, unencrypted file is such a good idea?