File permissions in Linux control access to files and directories by specifying who can read, write, or execute them. Permissions are set for three types of users:
- Owner: The user who owns the file.
- Group: Users who are part of the file's group.
- Others: All other users.
Types of Permissions:
- Read (r): Allows viewing the contents of a file.
- Write (w): Allows modifying or deleting the file.
- Execute (x): Allows running the file as a program.
Permission Representation:
Permissions are represented in a 3-character format for each user type, such as rwxr-xr--:
- The first three characters (
rwx) are for the owner. - The next three (
r-x) are for the group. - The last three (
r--) are for others.
Example:
To set permissions using the chmod command:
chmod 755 filename.txt
This command sets:
- Owner: read, write, execute (7)
- Group: read, execute (5)
- Others: read (5)
Summary:
By managing these permissions, you can control who can access or modify files, enhancing security and resource sharing on the system. If you have further questions, feel free to ask!
