Unix Permission Converter

Convert between symbolic (rwxr-xr-x) and octal (755) permission notation — with a full per-audience breakdown.

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Conversion

Type either form above — it converts both ways automatically with a full breakdown.

About this tool

ls -l shows rwxr-xr-x; chmod wants 755. This converter translates both directions automatically — type either form and get the other, plus a table explaining exactly what owner, group and others may do.

Special-bit letters (s, S, t, T) are fully supported, so 4-digit octals like 2775 round-trip correctly.

How to use it

  1. Type a symbolic string (with or without the leading file-type character) or an octal number.
  2. The converter detects the format and translates instantly.
  3. Read the per-audience breakdown table.
  4. Copy the equivalent chmod command.

Useful ways to apply it

  • Decoding ls -l output into a chmod-able number.
  • Verifying what 2755 or 4755 actually mean before applying them.
  • Teaching the relationship between the two notations.
  • Auditing permissions listed in deployment docs.

Frequently asked questions

What's the difference between s and S?
Lowercase s means the special bit AND execute are both set; uppercase S means the special bit is set but execute is not — usually a misconfiguration worth checking.
Can I paste ls -l output directly?
Paste the 10-character permission block (like -rwxr-xr-x or drwxr-xr-x) — the leading type character is accepted and ignored.
Why does my 4-digit octal show letters in the symbolic form?
The first digit encodes setuid/setgid/sticky, which appear as s/S in owner/group execute positions and t/T in the others position.

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