allow sudo to another user without password
I want to be able to 'su' to a specific user, allowing me to run any command without a password being entered.
For example:
If my login were user1 and the user I want to 'su' to is user2:
I would use the command:
su - user2
but then it prompts me with
Password:
sudo can do just that for you :)
It needs a bit of configuration though, but once done you would only do this:
sudo -u user2 -s
And you would be logged in as user2 without entering a password.
Configuration
To configure sudo, you must edit its configuration file via: visudo. Note: this command will open the configuration using the vi text editor, if you are unconfortable with that, you need to set another editor (using export EDITOR=<command>) before executing the following line. Another command line editor sometimes regarded as easier is nano, so you would do export EDITOR=/usr/bin/nano. You usually need super user privilege for visudo:
sudo visudo
This file is structured in different section, the aliases, then defaults and finally at the end you have the rules. This is where you need to add the new line. So you navigate at the end of the file and add this:
user1 ALL=(user2) NOPASSWD: /bin/bash
You can replace also /bin/bash by ALL and then you could launch any command as user2 without a password: sudo -u user2 <command>.
If you want to be able to switch to any user just use
user1 ALL=(ALL) NOPASSWD: /bin/bash
Update
I have just seen your comment regarding Skype. You could consider adding Skype directly to the sudo's configuration file. I assume you have Skype installed in your Applications folder:
user1 ALL=(user2) NOPASSWD: /Applications/Skype.app/Contents/MacOS/Skype
Then you would call from the terminal:
sudo -u user2 /Applications/Skype.app/Contents/MacOS/Skype
I would set up public/private ssh keys for the second account and store the key in the first account.
- Associating ssh public key with user account
Then you could run a command like:
ssh user@localhost -n /Applications/Skype.app/Contents/MacOS/Skype &
You'd still have the issues where Skype gets confused since two instances are running on one user account and files read/written by that program might conflict. It also might work well enough for your needs and you'd not need an iPod touch to run your second Skype instance.