How run sudo -s after ssh login

Question

My Step By Step:

1. On myserver.com i paste line "sudo -s" to file "~/.bashrc" in home directory for "mylogin"
2. SSH Login to mylogin@myserver.com

3. After login:

   root@myserver.com:~$

4. But, press cntrl+D for exit

   root@myserver.com:~$ exit

   root@myserver.com:~$ exit

   ...

   root@myserver.com:~$

   5.Do not quit.

Why?

Please, tell me the correct method.

Answer 1

The command sudo -s runs a new shell, which executes your .bashrc.

So what happened here, is that you created a loop where each new shell runs sudo -s, which in turn creates a new shell. At some point, the loop reached the RLIMIT_NPROC limit for the system, and the loop stopped, leaving a huge stack of nested shells. This limit is too high on most system (8192 or unlimited) for you to exit them using your keyboard.

Answer 2

You can store a flag in an environment variable:

if [ -z $INITIAL_SUDO ]; then
    exec sudo -s INITIAL_SUDO=1
fi

In this case, initial shell invoked by ssh won't have the INITIAL_SUDO flag on and it will spawn sudo process. Shell invoked by sudo, on the other hand, will have INITIAL_SUDO variable set and won't try to call sudo again.

Note that I call exec sudo -s instead of sudo -s. Otherwise, you'll have to press ctrl+D twice: first for a root shell and second for an initial shell which invoked sudo in the first place.