How can I install TLP in Ubuntu 18.04?
You are reading old instructions off the internet. tlp
is included in Ubuntu's universe repository so all you need to type is:
sudo apt install tlp
If you want to utilize the Radio Wizard also use:
sudo apt install tlp-rdw
Thinkpad users can install optional packages for battery threshold levels:
sudo apt-get install tp-smapi-dkms acpi-call-dkms
Source: Welcome to TLP!
For a person who is more into the UI, do the following.
$ sudo add-apt-repository ppa:linuxuprising/apps
$ sudo apt-get update
$ sudo apt-get install tlpui