Solved - ADB Devices fastboot Command not found error in Linux Ubuntu
You can use the following commands in Ubuntu, Linux Mint, Mx Linux and other debian based Linux distributions to install adb and fastboot.
Error 1: bash: adb: command not found
Press ctrl+alt+t to launch Terminal
sudo apt install android-tools-adb
Or
sudo apt install adb
Error 2; bash: fastboot: command not found
sudo apt install fastboot
sudo apt install android-tools-fastboot