How does Linux modify the ownership of a file?

With chmod commands. Below is pasted.

File directory permission setting command: chmod

This is one of the most common commands used by Linux system administrators to change access to a file or directory. There are two uses for this command:

Use text settings that include letters and operator expressions.

The syntax format is: chmod [who] [opt] [mode] file directory name.

where who stands for object, is one or a combination of the following letters:

u: indicates the owner of the file.

g: indicates the same group of users.

o: indicates other users.

a: indicates all users.

opt represents the operation, which can be:

Add a permission.

Revoke a permission.

Give the given permissions and cancel the original ones.

Mode stands for Permission:

r: readable w: writable.

x: executable.

For example, add read and write permissions to files for the same group of users

chmod g+rw

By the digital setting method.

The number setting rule is simpler: chmod [mode] file name.

The key is the value of mode, at first many beginners will be confused, in fact, it is very simple, we will see rwx as a binary number, if there is 1 is dedicated, if there is no 0 dedicated, then rwx r-x r- - can be represented as:

Every three digits are converted into a decimal number, which is 754.

For example, we want this file to have permissions to:

Self users in the same group and other users.

Readable Yes Yes Yes.

Writable Yes Yes executable.

So, we first get the permission string according to the above table: rw-rw-r--, then convert to a binary number is 110 110 100, and then convert every three digits to a decimal number, we get 664, so we execute the command:

chmod 664

There is no specific rename command.

You can rename it with mv a b.

mv: move to move files (extended function: rename, Linux system does not have a special rename command).

Basic format:moving files:mv filename Move destination filename.

Rename the file: MV filename The name of the modified file.

The steps for Linux file permissions are as follows:Computer: Macbook

System: OSX

1. Open the Linux system and right-click on the blank space of the Linux desktop.

2. In the pop-up drop-down options, click to open the terminal.

3. Use the cd command to move to the file path to be queried.

4. Use the ls -l or ll command to view the permissions of the file.

Linux definitions.

Linux is a free and open source UNIX-like operating system that was born on October 5, 1991 (the first time it was officially announced). With the help of the Internet network and the joint efforts of computer enthusiasts all over the world, it has now become the most used Unix operating system stool in the world today, and the number of users is still growing rapidly.

Strictly speaking, Linux refers to the Linux kernel, but most people are used to using Linux to refer to the system with Linux as the kernel There are many types of inux systems, Little Red Riding Hood Linux seems to be the best in Linux, Apple's system is based on the Linux kernel, and the domestic systems with Linux as the kernel include Red Star Linux, YMF-OS, etc., Linux systems are mostly free, The stability of the Linux kernel is a prominent advantage of the Linux system.

What are the file permissions for Linux? How do I change it?

Dear, hello, I'm glad to answer for you: What are the file permissions of linux? How do I change it?

Answer: The permissions of Linux files or directories are divided into read, write, and can be used. There are three types of file access: the file creator, the user in the same group as the file creator, and other users. The command to modify the permissions or directories of a file is as follows"" 。

755 indicates that "the creator has the read/write executable permission, and the same group of users and other users have the read and execute permissions." "755"How it is composed:"0"Indicates that there is no permission"1" indicates executable permissions"2" indicates writable permissions"4" indicates readable permissions.

7=1+2+4, 5=1+4”。use""The command is the same for users who can use the Linux system"Read and write executable permissions". Linux also has an easy way to understand how to assign permissions to files or directories.

For example: .chmoda-x"Indicates that all users will not have execution permissions for this file or directory.

a" for all users, and "u" for creator"g"Indicates that the creator is in the same group of users"o" for another user; "Indicates the permission to add"- Indication of the right to revoke; "r" indicates read permission"w" indicates write permissions"x"Indicates the write permission. I hope mine is helpful to you, I wish you a happy life, if mine is helpful to you I hope you can give a 5 star like. Thank you for your support.

1. chmod 777 + file name.

2. Folder permissions:

r==>readable w==> writable x==> executable r=4 w=2 x=1

777 stands for rwxr-rwx-rwx, read, write, executable for all users.

chmod +x filename.

or chmod 777 filename.

It has to be the owner of the file or a super user!

First of all, the file must belong to the owner or root user.

Then: chmod 777 filename.

The original meaning of the chmod command is "change the permissions mode of a file", which is simply called "change mode", which means a command to change the permissions of a file or directory, but only the owner of the file and the root superuser can execute this command. There are two modes, one is to take permission letters and operator expressions; The other is the adoption of numbers.

Syntax format: chmod [parameters] [files] common parameters:

c If the file permission has indeed been changed, the change action will be displayed - f If the file permission cannot be changed will not be displayed with an error message -v The details of the permission change will be displayed.

r Change the same permissions as all files and subdirectories in the current directory (i.e., change them one by one in a recursive manner).

root@linuxcool ] chmod a+r makes all files and subdirectories in the current directory readable by anyone:

root@linuxcool ] chmod -r a+r * sets the to be executed only by the owner of the file:

root@linuxcool ~]# chmod u+x

To modify the properties and permissions of a Linux file, perform the following steps:

Change the owner of the file. , and the command format is set to: chown owner file or directory. As shown in the figure, the directory owner was root, and the current chown is bin.

To modify the file permissions, change the command format to chmod permission properties file or directory. As shown in the figure, the original directory permission is rwxr-xr-x, which is later changed to rwxrwxrwx.

Use the [man] command to view the parameters and usage of chgrp, chown, and chmod.

The permissions and properties of the file have been modified.

Examples of file permissions.

Run the ls -al command to view the file properties as follows:

rwxrw-r‐-1 root root 1213 feb 2 09:39 abc

The first character represents the file (-), the directory (d), and the link (l).

The rest of the characters are read (r), written (w), and executed (x) in groups of 3

The first set of RWX: The file owner's permissions are read, write, and execute.

The second group of RW-: Users in the same group as the file owner have the permissions to read and write, but cannot execute.

The third group r--: the permissions of other users who are not in the same group as the file owner are read, write, and execute.

It can also be expressed numerically as: r=4, w=2, x=1 and therefore rwx=4+2+1=7

1 indicates the number of files connected.

root represents the user.

root indicates the group to which the user belongs.

1213 is the file size in bytes

Feb 2 09:39 indicates the date of the last modification.

abc stands for file name.

chmod u+x file adds execution permissions to the owner of the file.

chmod 751 file assigns the read, write, and execute permissions (7) to the owner of the file, the read and execute (5) permissions to the group to which the file belongs, and the execute permission (1) to other users.

chmod u=rwx,g=rx,o=x file as above.

chmod =r file assigns read access to all users.

chmod 444 file Ibid.

chmod a-wx, a+r file ditto.

chmod -r u+r directory recursively assigns read permissions to the owners of all files and subdirectories in the directory directory.

The chmod command is used to modify the file permissions, for example, to change the file permissions of home user1 to 777, which needs to be executed

1chmod 777 /home/user1/