Changing to root user inside shell script

Question

I have a shell script which needs non-root user account to run certain commands and then change the user to root to run the rest of the script. I am using SUSE11. I have use

Answer 1

sudo will work here but you need to change you script a little bit:

$ cat 1.sh 
id 
sudo -s <

You need to run your command in < block and give the block to sudo.

If you want, you can use su, of course. But you need to run it using expect/pexpect that will enter password for you.

But even case you could manage to enter the password automatically (or switch it off) this construction would not work:

user-command
su 
root-command

In this case root-command will be executed with user, not with root privileges, because it will be executed after su will be finished (su opens a new shell, not changes uid of the current shell). You can use the same trick here of course:

su -c 'sh -s' <

But now you have the same as with sudo.