os_cp:users_permissions
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os_cp:users_permissions [2023/04/02 11:10] jkonczak utworzono |
os_cp:users_permissions [2025/03/31 14:30] (current) jkonczak |
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| A user is identified by a numerical __u__ser __id__entifier – **uid**. Uids are mapped to usernames. | A user is identified by a numerical __u__ser __id__entifier – **uid**. Uids are mapped to usernames. | ||
| \\ | \\ | ||
| - | A group is identified by a numerical __g__roup __id__entifier – **uid**, that are likewise mapped to group names. | + | A group is identified by a numerical __g__roup __id__entifier – **gid**, that are likewise mapped to group names. |
| A user must be in one primary group and can be in multiple supplementary groups. | A user must be in one primary group and can be in multiple supplementary groups. | ||
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| <html></small></html> | <html></small></html> | ||
| - | The user whose uid equals **0** is referred to as **superuser**. Traditional username of the superuser is **[[https://pl.wikipedia.org/wiki/Root|root]]**. | + | The user whose uid equals **0** is referred to as **superuser**. Traditional username of the superuser is **[[https://en.wikipedia.org/wiki/Superuser|root]]**. |
| To check who you are, you can run the ''**whoami**'' command. \\ | To check who you are, you can run the ''**whoami**'' command. \\ | ||
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| <html><small></html> | <html><small></html> | ||
| | | ||
| + | ++++ Examples: | {{section>so:users_chmod:examples-en#id&inline&noheader}} ++++ | ||
| + | |||
| ==== [extra] Logged on users, logon history, messaging others ==== | ==== [extra] Logged on users, logon history, messaging others ==== | ||
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| <html></small></html> | <html></small></html> | ||
| + | |||
| + | ++++ Examples: | {{section>so:users_chmod:examples-en#who&inline&noheader}} ++++ | ||
| ==== Switching to another user ==== | ==== Switching to another user ==== | ||
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| <html></small></html> | <html></small></html> | ||
| + | |||
| + | ++++ Examples: | {{section>so:users_chmod:examples-en#su&inline&noheader}} ++++ | ||
| ===== File permissions ===== | ===== File permissions ===== | ||
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| \\ | \\ | ||
| <small>Additionally, there are three other special permissions: set-user-id (suid, __**s**__), set-group-id (sgid, __**s**__) and sticky (__**t**__).</small> | <small>Additionally, there are three other special permissions: set-user-id (suid, __**s**__), set-group-id (sgid, __**s**__) and sticky (__**t**__).</small> | ||
| + | |||
| + | Upon file access, when the file belongs to the current user, only user's permissions are considered.\\ | ||
| + | If the file does not belong to the user but the user belongs to the file's group, only group's permissions are considered.\\ | ||
| + | If the file does not belong to the user and the user does not belong to the file's group, only others' permission are considered.\\ | ||
| + | <small>Note that if a file has read permission for the group but no read permission for the user, then the owner cannot display the file even if the owner belongs to the file's group.</small> | ||
| The execute mode for files stands for running them (e.g., as a program or a script), for directories – entering it. | The execute mode for files stands for running them (e.g., as a program or a script), for directories – entering it. | ||
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| </small> | </small> | ||
| + | |||
| + | <html><style>.wrap_nomargin{margin:0} .wrap_nomargin p{margin:0}</style></html> | ||
| + | <WRAP nomargin> | ||
| + | Examples: | ||
| + | ++++ umask | {{section>so:users_chmod:examples-en#umask&inline&noheader}} ++++ | ||
| + | ++++ manipulating mode bits | {{section>so:users_chmod:examples-en#chmod&inline&noheader}} ++++ | ||
| + | ++++ user, group or others | {{section>so:users_chmod:examples-en#ugo&inline&noheader}} ++++ | ||
| + | ++++ write-only and read-only files | {{section>so:users_chmod:examples-en#write_only&inline&noheader}} ++++ | ||
| + | ++++ creating/removing directory entries | {{section>so:users_chmod:examples-en#dir_create_remove&inline&noheader}} ++++ | ||
| + | </WRAP> | ||
| + | ++++ suid and sgid | {{section>so:users_chmod:examples-en#suid_sgid&inline&noheader}} ++++ | ||
| + | |||
| ===== Change, modify and access date ===== | ===== Change, modify and access date ===== | ||
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| <html></small></html> | <html></small></html> | ||
| + | |||
| + | ++++ Examples: | {{section>so:users_chmod:examples-en#touch&inline&noheader}} ++++ | ||
os_cp/users_permissions.1680426650.txt.gz · Last modified: 2023/04/02 11:10 by jkonczak
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