jenkins.sh

#! /bin/bash

# Copy files from /usr/share/jenkins/ref into /var/jenkins_home
# So the initial JENKINS-HOME is set with expected content. 
# Don't override, as this is just a reference setup, and use from UI 
# can then change this, upgrade plugins, etc.
copy_reference_file() {
	f=${1%/} 
    rel=${f:23}
    dir=$(dirname ${f})
	if [[ ! -e /var/jenkins_home/${rel} ]] 
	then
		mkdir -p /var/jenkins_home/${dir:23}
		cp -r /usr/share/jenkins/ref/${rel} /var/jenkins_home/${rel}; 
	fi; 
}
export -f copy_reference_file
find /usr/share/jenkins/ref/ -type f -exec bash -c 'copy_reference_file {}' \;

# if `docker run` first argument start with `--` the user is passing jenkins launcher arguments
if [[ $# -lt 1 ]] || [[ "$1" == "--"* ]]; then
   exec java $JAVA_OPTS -jar /usr/share/jenkins/jenkins.war $JENKINS_OPTS "$@"
fi

# As argument is not jenkins, assume user want to run his own process, for sample a `bash` shell to explore this image
exec "$@"