Switch to root user within bash script

Question

Im currently logged in as admin and I want to edit the /etc/hosts file which required root access.

I'm not able to make the changes. The script gets executed sucessfully but the changes arent made.

My Script - Runs Sucessfully when executed from terminal

sudo -s
echo "127.0.0.1" >> /etc/hosts
su admin

sudo -s - switches to root without password when executed from terminal

su admin - switches back to admin user when run on terminal

My /etc/hosts file remains empty after running the script

Answer 1

There is no need to actually switch your user within the script.
Also, you can't echo something as root like that because the redirect ( >> ) is executed by the shell.

A possible workaround is using tee :

echo "127.0.0.1" | sudo tee -a /etc/hosts

Further explanation:

tee basically takes the data from the standard input and writes it either to the standard output, or to a file. For more information see the commands manual ($ man tee )