Terminal commandline basics

Sometimes, actually, it's lowercase. Other times, it has someone else's login. Like it'll be "jdoe" for some reason. Why does it change like开发者_开发知识库 that? This is my work computer, if that explains anything. Thanks!

If you're talking about your commandline prompt: http://www.ibm.com/developerworks/linux/library/l-tip-prompt/