Permissions analysis for Linux files and directories

Linux permissions: As the name implies is the ability to give users the right to access the specified files and directories and no right to access the specified files and directories

Here's a look at what general permissions are under Linux

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Let's take a look at the special permissions for files in Linux:

SUID: Temporarily allow certain users to execute files as Administrator with the permission of the owner of the file, but cannot add parameters to determine the identity of the initiator

Example:-rwsr-xr-x. 1 root root 30768 Feb 2012/usr/bin/passwd
Give SUID permission
chmod u+s FILE ...

Sgid: Common: Directory settings Sgid All users in this directory, the genus group that created the file is a group of directories
chmod g+s FILE ...

Sticky: Sticky bit

chmod o+t FILE ...

suid | Sgid | Sticky
4 2 1

You can use numbers to change

Example: chmod 7777 a.txt

-rwsrwsrwt.1 root root 5 Apr 09:52 a.txt

This file represents the permission to have suid sgid and sticky bits

Permissions match:

Check the owner-"Check access list of the owner-" inspection group-"Check access list of the genus group-" Check other users-"Check access list other users

Additionally, the file has extended properties that can be lsattr to display chattr to change

A: File content is not allowed to be added only
C: Compression format
D: No Backup
E: Extended Format
I: Prevent administrators from forcibly writing
J: Data Log
S: Safe removal
T: Merge is not performed at the tail
A: Do not update the access timestamp
u: Prevent administrators from deleting
D: Directory synchronization update
S: File Sync update
T: Directory set to top-level directory

In addition, FACL allows users to have additional access mechanisms

Getfacl Show Access list

Setfacl Setting Access lists
Format:

SETFACL-Option U or g: User name or group name: Permissions FILE ...

Options:

-M add additional access authorizations

-X Cancel Authorization

-R recursive settings (for directory settings)

Summarize:

Linux has more and more privileges. These are just superficial permission settings, specifically the reader's own man for each set of commands and usage.

This article is from the "Linux_mayi" blog, make sure to keep this source http://jlxmy.blog.51cto.com/8497132/1634872

Permissions analysis for Linux files and directories