 | | A UNIX system maintains several pieces of information about each user, including a login name, user ID, and one or more group IDs. The operating system uses this data to keep track of the privileges associated with each process (what files it may open, how many resources it may consume, etc.), who is currently logged in, when each user last logged in, and so on. In this chapter, we examine the information maintained by the operating system about users, and what it may be used for. | |
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