Symbolic Notation
-rw-rw-rw-(as shown by ls -l)-rw-rw-rw-
typeownergroupother
Permission Matrix
| Read(4) | Write(2) | Execute(1) | Octal | |
|---|---|---|---|---|
| Owner | r | w | - | 6 |
| Group | r | w | - | 6 |
| Other | r | w | - | 6 |
What Does chmod 666 Mean?
Owner can read, write. Group can read, write. Others can read, write.
$ chmod 666 filenameCommon Use Cases
Everyone can read and write. Rarely appropriate — sometimes used for device files like /dev/null.
Security Notes
Dangerous — any user can modify the file. Avoid for anything meaningful; prefer 644 or 660 instead.
Interactive Tool
Need to calculate a custom permission? Use the interactive permissions calculator to toggle individual bits and get instant results.
Unix Permissions Calculator