I wanted to show the user who triggered a Jenkins job in the post job email. This is possible by using the plugin Build User Vars Plugin and the env variable
Build user vars plugin wasn't working for me so I did a quick-and-dirty hack:
BUILD_CAUSE_JSON=$(curl --silent ${BUILD_URL}/api/json | tr "{}" "\n" | grep "Started by")
BUILD_USER_ID=$(echo $BUILD_CAUSE_JSON | tr "," "\n" | grep "userId" | awk -F\" '{print $4}')
BUILD_USER_NAME=$(echo $BUILD_CAUSE_JSON | tr "," "\n" | grep "userName" | awk -F\" '{print $4}')