A path set in /etc/profile/ doesn't appear on other users' environment

Question

I have the following PATH variable in /etc/profile. The last line should allow me to use the conda command for any user.

# /etc/profile: system-wide .profile file for the Bourne shell (sh(1))
# and Bourne compatible shells (bash(1), ksh(1), ash(1), ...).

if [ "${PS1-}" ]; then
  if [ "${BASH-}" ] && [ "$BASH" != "/bin/sh" ]; then
    # The file bash.bashrc already sets the default PS1.
    # PS1='\h:\w\$ '
    if [ -f /etc/bash.bashrc ]; then
      . /etc/bash.bashrc
    fi
  else
    if [ "`id -u`" -eq 0 ]; then
      PS1='# '
    else
      PS1='$ '
    fi
  fi
fi

if [ -d /etc/profile.d ]; then
  for i in /etc/profile.d/*.sh; do
    if [ -r $i ]; then
      . $i
    fi
  done
  unset i
fi

export PATH=/opt/miniconda3/bin:$PATH

It works when I'm root :

root@server:~# echo $PATH
/opt/miniconda3/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin

But when I do su user to become user:

user@server:/root$ echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games

/opt/miniconda3/bin: doesn't appear in $PATH variables as you can see. Shouldn't variables defined in /etc/profile be available system-wide ? How can I get it so ?

Answer 1

When you use su user, the resulting environment is not the same as when you start a login shell. Specifically, according to man su:

   The current environment is passed to the new shell. The value of $PATH
   is reset to /bin:/usr/bin for normal users, or
   /sbin:/bin:/usr/sbin:/usr/bin for the superuser. This may be changed
   with the ENV_PATH and ENV_SUPATH definitions in /etc/login.defs.

To get a login shell environment hen using su (in particular, to read the /etc/profile file) you can use su - user or su -l user:

   -, -l, --login
       Provide an environment similar to what the user would expect had
       the user logged in directly.