[SOLVED] Exported variable in bashrc file not visible when running as another user

Issue

On Ubuntu 20.04LTS:

• Create a dummy user.
• Create a short script that appends an exported variable to the new user's .bashrc, then sources that .bashrc and tries to use the variable.
• Run the script as the new user.

Why is the variable not set?

> adduser --gecos ',,,' --disabled-password foouser
[...output...]
> cat > /tmp/bootstrap.sh <<EOF
  echo 'export FOO=foo' >> /home/foouser/.bashrc
  . /home/foouser/.bashrc
  echo 'sourced foouser bashrc'
  set | grep FOO
EOF
> chmod a+x /tmp/bootstrap.sh
> su - foouser -c /tmp/bootstrap.sh
[...output does not include FOO...]
> deluser --remove-home foouser

Solution

Your problem is that .bashrc is configure explicitly to only run for interactive shells. Look at the top of /home/foouser/.bashrc:

# If not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;
esac

If you add a set -x to your /tmp/bootstrap.sh script, you will see when you execute it the following:

+ echo 'export FOO=foo'
+ . /home/foouser/.bashrc
++ case $- in
++ return
+ echo 'sourced foouser bashrc'
sourced foouser bashrc
+ set
+ grep FOO

There you can see it hits the return command in the case statement.

You can force an interactive shell with the -i option:

root@ed3085a447ad:/# su - foouser -c 'bash -i -c /tmp/bootstrap.sh'
bash: cannot set terminal process group (-1): Inappropriate ioctl for device
bash: no job control in this shell
sourced foouser bashrc
FOO=foo

Answered By - larsks

Answer Checked By - Mildred Charles (WPSolving Admin)