How to pass the password to su/sudo/ssh without overriding the TTY?

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I'm writing a C Shell program that will be doing su or sudo or ssh. They all want their passwords in console input (the TTY) rather than stdin or the command line.

Does anybody know a solution?

Setting up password-less sudo is not an option.

could be an option, but it's not present on my stripped-down system.

22 Answers

I wrote some Applescript which prompts for a password via a dialog box and then builds a custom bash command, like this:

echo <password> | sudo -S <command>

I'm not sure if this helps.

It'd be nice if sudo accepted a pre-encrypted password, so I could encrypt it within my script and not worry about echoing clear text passwords around. However this works for me and my situation.

I've got:

ssh user@host bash -c "echo mypass | sudo -S mycommand"

Works for me.

The usual solution to this problem is setuiding a helper app that performs the task requiring superuser access: http://en.wikipedia.org/wiki/Setuid

Sudo is not meant to be used offline.

Later edit: SSH can be used with private-public key authentication. If the private key does not have a passphrase, ssh can be used without prompting for a password.

Take a look at expect linux utility.

It allows you to send output to stdio based on simple pattern matching on stdin.

Set SSH up for Public Key Authentication, with no pasphrase on the Key. Loads of guides on the net. You won't need a password to login then. You can then limit connections for a key based on client hostname. Provides reasonable security and is great for automated logins.

a better sshpass alternative is: passh https://github.com/clarkwang/passh

Login to a remote server

 $ passh -p password ssh user@host

Run a command on remote server

 $ passh -p password ssh user@host date

other methods to pass the password

-p The password (Default: `password')

-p env: Read password from env var

-p file: Read password from file

here I explained why it is better than sshpass, and other solutions.

You can also pass various parameters as follows:

echo password | echo y | sudo -S pacman -Syu

(Although that's a bad idea, it's just an example)

Building on @Jahid's answer, this worked for me on macOS 10.13:

ssh <remote_username>@<remote_server> sudo -S <<< <remote_password> cat /etc/sudoers

I once had a use case where I needed to run Sudo and ssh in the same command without stdin specifying all the variables needed.

This is the command I used

echo sudopassword | sudo -S -u username sshpass -p  extsshpassword ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no  username@ipaddress " CMD on external machine"

Breaking that command into pieces!

This will allow you to run commands through your machine using Superuser:

echo password | sudo -S -u username

This will allow you to pass ssh password and execute commands on external machines:

sshpass -p  sshpassword  ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no  username@ipaddress " CMD on external machine"

make sure you install the sudo and openssh packages on your machine.

You can provide password as parameter to expect script.

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