Chmod Permissions Calculator
Interactive Unix / Linux file permissions calculator. Convert octal numbers, symbolic notation, and special bits in real-time.
| Role | Read (4) | Write (2) | Execute (1) |
|---|---|---|---|
| Owner (u) | |||
| Group (g) | |||
| Public / Others (o) |
About This Tool
Builds Unix file permissions visually: select read, write, and execute permissions per role (owner, group, others), or pick a common preset, and get the octal number, symbolic string, and ready-to-run chmod commands back immediately. Typing directly into the Octal field works too; it re-parses and syncs the checkboxes back.
Binary bit values map to three core permissions: 4 = Read (r), 2 = Write (w), and 1 = Execute (x). Special bits form a leading fourth octal digit: SetUID (4000) runs files with owner privileges, SetGID (2000) inherits group ownership, and the Sticky Bit (1000) prevents deletion of files by non-owners in shared directories like /tmp.
Key Features
- Interactive RWX Matrix: Nine checkboxes (owner, group, and others by read, write, execute) calculate permissions in real time.
- Eight Common Presets: Quick presets for 755 executable, 644 standard file, 600 private key, 700 private directory, 777 public, and 1777 sticky.
- Bidirectional Sync: Type octal numbers directly to update checkboxes or click checkboxes to update octal values.
- Special Bits Support: SetUID (s/S), SetGID (s/S), and Sticky Bit (t/T) automatically switch output to 4-digit octal notation.
- Target Filename Customizer: Pre-fill target script or file name into both numeric and symbolic bash command formats.
- Per-Field Copy: Instant clipboard copy buttons for octal values, symbolic strings, and ready-to-paste chmod CLI commands.
