hddtemp on my Arch Linux, but it needs to be run with root permissions. I want to execute it as a normal user without using
sudo. How can I do this?
You can make the program SUID. This is NOT a very safe way to do things, since SUID programs can often unintentionally open ways to escalate privileges, especially if the program wasn't intended to be run SUID. Unless the sudo solution is unacceptable for some reason (it's hardcoded into a script/program that you can't change), you should go with that. You can even make a script to hide the fact that sudo is being used if necessary.