Permission-owner, group member, and all other users

When a file has a file or directory, it has control over the access to the file or directory.

Owner

In the unix security model, a user can own (own) files and directories.

When a file has a file or directory, it has control over the access to the file or directory.

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Group members

In turn, the user belongs to another group. This group is composed of one or more user groups.

Users in the group are authorized to access files and directories by their owner.

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All other users

In addition to authorizing group Access, the file owner can also grant some access permissions to all users.

In unix terms, all user values are in the world.

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Use id to obtain user identity information

[Root @ allyes20121031 de_info_center] # id

Uid = 0 (root) gid = 0 (root) groups = 0 (root), 1 (bin), 2 (daemon), 3 (sys), 4 (adm ), 6 (disk), 10 (wheel)

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Where does this information come from?

Similar to many situations in linux, this information comes from a series of text files.

The user account is defined in/etc/passwd, and the user group is defined in/etc/group.

Many Unix-like systems allocate common users to a public group, such as uesrs.