bash script to log as another user and keep the terminal open-CodePudding

I have set up a http server at localhost, with several sites. I would like to connect to each site root folder, at the same way I used to at a remote server via ssh. So, I tried to create a bash script, intended to log as user "http", giving the site root folder as argument and change the $HOME to the site root folder:

#!/bin/bash
echo "Connecting to $1 as http...";
read -p "Contraseña: " -s pass;
su - http << EOSU >/dev/null 2>&1
$pass
export HOME="/srv/http/$1";
echo $HOME;
source .bash_profile;
exec $SHELL;
EOFSU

It does not work, basically because of:

echo $HOME keeps giving out the home folder of the user launching the script.
when the script reaches the end, it ends (obvious), but I would like that it stays open, so I could have a terminal session for user "http" and go on typing commands.

In other words, I am looking for a script that saves me 3 commands:

# su - http
# cd <site_root_folder>
# export HOME=<site_root_folder>

CodePudding user response：

If you need to script some commands and then change to an interactive session then pyexpect would be your best solution.

This example may give you some ideas.

CodePudding user response：

Your main problem is that the $HOME is evaluated as when the user run the script, meaning that it will get his evaluation of $HOME instead of evaluating it as the given user.

You can evaluate the $HOME as the given user (using the eval command) but I wont recommend it, it is generally bad practice to use this kind of evaluation, especially when talking about security.

I can recommend you to get the specific user home directory with standard linux tools like passwd

Example of the behavior you are seeing:

# expected output is /home/eliott
$ sudo -u eliott echo $HOME
/root

Working it around with passwd:

$ sudo -u eliott echo $(getent passwd eliott | cut -d: -f6)
/home/eliott

CodePudding user response：

Here's a way to do it with a bash init file generated on-the-fly:

#!/bin/bash

su http -- --init-file <(cat <<EOF
    export HOME=$(printf '%q' "/srv/http/$1")
    cd "\$HOME"
    . .bash_profile
EOF
)

notes:

With a bash init file you have to use su http instead of su - http
For expanding $1 in your context you need to escape it with printf '%q' "$1"
As you don't want $HOME to be expanded by the current shell, you need to write it as \$HOME in the here-document