I created a script, as follows
# start selenium
./node_modules/protractor/bin/webdriver-manager start > /dev/null 2>&1 &
# wait until selenium is up
while ! curl http://localhost:4444/wd/hub/status &>/dev/null; do :; done
# run the build
grunt cibuild --force
# stop selenium
curl -s -L http://localhost:4444/selenium-server/driver?cmd=shutDownSeleniumServer > /dev/null 2>&1