Ubuntu 18.04: Installer does not find JRE
Looking at the messages above, it seems you don't use bash as you login shell; could you try typing chsh at a command prompt and switch to /bin/bash if you have another shell?
Of course you must first check that bash is installed on your system by trying to execute it directly, or typing which bash
Then try again to install System Workbench for STM32
Bernard (Ac6)