Change source reference in install_venvburrito to dot (they are synonyms in bash, dot available in more shells). Unsure why this is being source'd here (line added in 0567c582f97cc5a70c72cb6fe905f94905b6a4fa by @chapmanb). If the goal was just to activate the burrito, might be better to replace this with env.safe_run('. $HOME/.venvburrito/startup.sh')?