These classnotes are depreciated. As of 2005, I no longer teach the classes. Notes will remain online for legacy purposes

UNIX01/UIDs And GIDs

Classnotes | UNIX01 | RecentChanges | Preferences

When you log in as user 'frank', UNIX does not implicitly see you as user 'frank'. Instead, UNIX looks up your username from a file and obtains a numeric user ID, or UID, for you. From that point on, when you do things on that UNIX system, you do them as your UID.

Likewise, when you log in as user 'frank', you could be a part of a group of users known as 'mainoffice'. UNIX looks up your group from another file of group names and obtains a numerica group ID, or GID, for you. Again, from that point on, everything you do will be done as a member of the your GID group.

So, to UNIX, all users and groups are simple integer numbers. We will examine the common methods for adding and manipulating the groups and users on your UNIX system in UNIX02 (for a preview, read UNIX02/User Accounts And Groups).



Classnotes | UNIX01 | RecentChanges | Preferences
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Last edited July 18, 2003 7:53 pm (diff)
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