chmod 000 filename| Entity | r | w | x | Octal | Permissions |
| Owner | 0 | 0 | 0 | 0 | --- (none) |
| Group | 0 | 0 | 0 | 0 | --- (none) |
| Others | 0 | 0 | 0 | 0 | --- (none) |
| Octal | Symbolic | Binary | Description |
|---|---|---|---|
| 0 | --- | 000 | No permissions |
| 1 | --x | 001 | Execute only |
| 2 | -w- | 010 | Write only |
| 3 | -wx | 011 | Write + Execute |
| 4 | r-- | 100 | Read only |
| 5 | r-x | 101 | Read + Execute |
| 6 | rw- | 110 | Read + Write |
| 7 | rwx | 111 | Read + Write + Execute |
Ideal for web server directories: owner can write, others can only read and traverse.
Select read, write, and execute permissions separately for owner, group, and others. Read the octal and symbolic results before copying the command. The example below enables all owner permissions while giving group and others only read and execute. Each digit is the sum of read as four, write as two, and execute as one, so you can check the result without running a command.
Apply the result to the intended path in your own terminal; this calculator does not change a file. Directory execute permission allows traversal and has different practical consequences from executing a program file. Check the owner, group membership, and any additional access rules on your system before interpreting the result. Avoid adding write permission broadly just to work around an unrelated ownership or deployment problem.
Owner: rwx; group: r-x; others: r-x
Octal: 755
Symbolic: rwxr-xr-x
chmod 755 means the owner has read (4), write (2), and execute (1) = 7; group has read and execute = 5; others have read and execute = 5. Common for web server directories.
Octal notation uses numbers (e.g., 755) where each digit encodes three permission bits. Symbolic notation uses letters (e.g., rwxr-xr-x) that are more human-readable.
Avoid chmod 777 in production — it allows any user to modify or delete the file. Use it only in development environments or for truly public temporary files.
Setuid (4xxx) makes executables run as the file owner. Setgid (2xxx) makes files inherit the group of the directory. Sticky bit (1xxx) on directories prevents users from deleting others's files (used on /tmp).
No. It calculates numeric and symbolic permission values; you apply them to a path in your own terminal. Inspect ownership and group membership before doing so. For a directory, execute allows traversal rather than launching a program. Additional access controls on the destination system can affect effective permissions beyond the displayed bits.