What is chmod 777 in Linux terminal?

chmod 777 is a command used in Linux to set file or directory permissions. It grants read (r), write (w), and execute (x) permissions to owner, group, and others.

Linux permissions are divided into three types:

• Read (r) – view the contents of a file or list a directory

• Write (w) – modify a file or create/delete files in a directory

• Execute (x) – run a file as a program or enter a directory

Each permission is represented by a number:

• r = 4

• w = 2

• x = 1

What 777 Means

The number 777 is a combination of permissions for owner, group, and others:

Owner  = 7 (4+2+1 → rwx)
Group  = 7 (4+2+1 → rwx)
Others = 7 (4+2+1 → rwx)

This means everyone has full access to the file or directory.

Using chmod 777

To apply chmod 777 to a file or directory:

chmod 777 filename
chmod 777 /path/to/directory

Verify Permissions

Check the permissions with:

ls -l filename

You should see:

-rwxrwxrwx 1 user group size date filename

Example Usage

Suppose you want to share a folder for testing:

mkdir shared
chmod 777 shared
echo "Hello World" > shared/file.txt
cat shared/file.txt

All users can now read, write, and execute files inside shared.

chmod 777 gives full read, write, and execute permissions to everyone. Use it carefully, as it can pose security risks if applied to sensitive files or directories.