Unix File Permissions (chmod) Explained
Understand octal and symbolic notation for Unix file permissions.
Unix file permissions control who can read, write, and execute files. Each permission set applies to three groups: owner, group, and others.
Permission values
- r (read) = 4
- w (write) = 2
- x (execute) = 1
- 755 = rwxr-xr-x (owner full, others read+execute)
- 644 = rw-r--r-- (owner read+write, others read only)