How to Set and Change RWX Permissions?

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Summary: If you've worked with macOS or Linux, you may come across many file and directory permissions, like RWX permissions. Let iBoysoft walk you through a brief introduction to RWX permissions, especially how to use them well.

 

File system permissions determine who can access a file on your computer. One of the most common permission models used is the RWX permissions. The RWX model represents three types of permissions:

  • R (Read): Allows viewing the contents of a file or listing the contents of a directory.
  • W (Write): Grants the ability to modify a file or create/delete files in a directory.
  • X (Execute): Allows execution of a file as a program or access to a directory.

And these permissions are assigned to three categories of users:

  • User (u): The file owner.
  • Group (g): Users who are part of the file's group.
  • Others (o): All other users on the system.

A typical permissions string looks like rwxr-xr--, where each trio of letters corresponds to users, group, and others respectively.

How does RWX translate to numbers?

Your operating system also uses a numeric (octal) representation of permissions. Each permission is assigned a value:

Read (r) = 4
Write (w) = 2
Execute (x) = 1

By summing these values, each set of permissions is represented by a number from 0 to 7:

rwx = 4 + 2 + 1 = 7
rw- = 4 + 2 = 6
r-- = 4 = 4

What are 755 and 644 permissions? This leads to common permission notations like:

  • 755 = rwxr-xr-x: Full access for the owner, read/execute for group and others.
  • 644 = rw-r--r--: Read/write for the owner, read-only for group and others.
  • 700 = rwx------: Full access only for the owner.

Have you got the numbers' meaning? Please share our post.

How to give, set, and change RWX permissions on Mac?

If you wanna change the RWX permissions on Mac, then follow in Terminal.

  1. Finder > Applications > Utilities > Terminal. 
  2. Type ls -l filename to see current RWX permissions for a file or a directory. 
    (Replace the filename with the specific name.) 
  3. Analyze the output commands, for example: -rwxr--r--  1 user staff  1024 May 6 10:00 filename. 
    [This means Owner has rwx (read, write, execute); Group has r-- (read-only); Others have r-- (read-only)] 
  4. To change RWX permissions, use the chmod commands. Use the numbers we talked about above, like chmod 755 filename  # rwxr-xr-x.

RWX permissions vs File permissions

RWX is a shorthand for describing file permissions, so they are not different concepts but are closely tied. File permissions use RWX to define what actions are allowed on a file or directory.

TermMeaning
RWXThe symbolic representation of permissions: Read (r), Write (w), Execute (x) 
File permissionThe complete access rules assigned to a file (e.g., rwxr-xr--, 644) 

Sum: RWX is the building block of file permissions.

Understanding RWX permissions is essential for anyone. By learning how to read, set, and modify these permissions, you can better secure your files, control access, and maintain proper system hygiene. Please share our post.