Jenkins - Change port
I tend to run several things locally, Jenkins among them. In fact, I even have a portable Jenkins that I carry around on a USB, unfortunately port allocation tends to be a problem, so this is how one would change the default port of Jenkins which is 8080.
java -jar -httpPort=8181 jenkins.war
Windows: open up Jenkins.xml in your editor of choice and find and replace the following with whichever port one desires.
Linux: Still applies, but file will be named depending on distro.