{"id":109693,"date":"2022-06-14T09:00:51","date_gmt":"2022-06-14T03:30:51","guid":{"rendered":"https:\/\/data-flair.training\/blogs\/?p=109693"},"modified":"2022-06-14T09:57:21","modified_gmt":"2022-06-14T04:27:21","slug":"chmod-in-linux","status":"publish","type":"post","link":"https:\/\/data-flair.training\/blogs\/chmod-in-linux\/","title":{"rendered":"Chmod in Linux"},"content":{"rendered":"

In this article, you will learn what Linuchmod is and its use, and understand the different file permissions. We will also see the syntax of the chmod command and the options used along with it. We shall also see how to change the file permissions and modify them accordingly.<\/p>\n

What is chmod in Linux?<\/h3>\n

In UNIX-like operating systems, there is a set of instructions or in Linux language – \u201cflags\u201d. These flags are associated with each file and determine who can open them and how can they access them. These flags are called \u2018modes\u2019 or \u2018permissions\u2019<\/p>\n

Chmod is the abbreviation for Change Mode. it is a command which allows you to change the access permissions of files and directories.<\/p>\n

In fact, if you run the command: \u201cls -l\u201d in the terminal you get this output:<\/p>\n

\"ls<\/a><\/p>\n

So when we list the contents of the desktop directory, you can see a prefix to each of the content there in the form of \u201c-rw-rw-r–\u201d, these are the file permissions that determine who can open and how can they access them.<\/p>\n

Why use Linux chmod?<\/h3>\n

With chmod, you have the freedom to authorize users according to your needs. You are the master of everything, you can be specific as to who reads, writes, or executes the files. In a nutshell, you can change the access permissions of a file system as per your liking.<\/p>\n

Understanding file permissions<\/h3>\n

Before we even touch on the syntax and options related to chmod, let us get a better understanding of the permission of a file system.<\/p>\n

Let us take the above file permissions: \u201c-rw-rw-r–\u201d. On closer observation, we can see that this file permission is a combination of 3 specific sets of instructions as follows: \u201drw\u201d, \u201crw\u201d and \u201cr–\u201d. The first hyphen also gives us information regarding the file type, however, the subsequent hyphens simply act as null values (as in there is no permission).<\/p>\n

Before we even look into what \u2018r\u2019 and \u2018w\u2019 are, let us see what these 3 sets of permission do. The 1st set of permissions is for the user, the 2nd set is for the group and the 3rd set is for others. Let us look into each of these.<\/p>\n

User<\/h4>\n

The user is the owner of the file. By default, the person who creates the file or directory becomes the owner. Therefore a user is also called the owner.<\/p>\n

Group<\/h4>\n

A group can contain multiple users. Say you have a project and a number of people need access to a file. Instead of individually assigning permissions to each of them, you can simply add all the users in a group and assign group permissions.<\/p>\n

Other<\/h4>\n

As the name suggests, it is for any other user who has access to the file. This user has nighter created a file, nor do they belong to a group. So basically, when you set the other permissions, it applies to the rest of the world.<\/p>\n

Now there is 1 minuscule topic left before we look at what \u2018r\u2019 and \u2018w\u2019 are. What does the first hyphen represent?<\/p>\n

If you look carefully at the contents of the desktop directory, the directories \u201cmovies\u201d and \u201cother\u201d have the same set of permissions, except for one difference: \u201cdrwxrwxr-x\u201d, the first hyphen was replaced with a d, indicating it is a directory and not a file: here is what each file type is denoted by:<\/p>\n