How are setuid, setgid, and sticky shown?

In symbolic form they appear as s, s, and t in place of the execute bit. The four-digit octal (for example, 4755) makes them explicit. Uppercase S/T indicates the special bit is set but the corresponding execute bit is not.

Is my input sent anywhere?

No. The calculator runs in the browser; nothing is transmitted.

What does chmod 644 mean?

Owner gets read+write (6), group and others get read only (4). Symbolically that is rw-r--r--.

Does it explain individual bits?

Yes. Each of the nine permission positions is labelled, and toggling any cell instantly updates the octal value so you can build a permission set interactively.

octal · symbolic · chmod · setuid · live

Convert Unix file permissions

Switch between octal (755) and symbolic (rwxr-xr-x) chmod notation. Handles setuid, setgid and sticky bits. Runs locally in your browser.

Unix Permissions Converter

Input

755

octal

Octal

755

chmod

Symbolic

rwxr-xr-x

ls -l

Status

valid

live

input · permission

Enter either octal (3 or 4 digits) or 9-char symbolic.

output · forms

Octal755

Symbolicrwxr-xr-x

Quick Start

How to read chmod numbers

Octal compresses each rwx triplet into one digit (r=4, w=2, x=1). Add a prefix digit for setuid/setgid/sticky.

01
Type a value
Either 3-digit octal like 755, 4-digit like 4755, or 9-char rwxr-xr-x.
Parsing is strict-but-tolerant — comments and trailing commas are accepted on input where the source format historically permits them; output stays canonical.
inputstricttolerantliveparse
input · source755 · live
```
755
```
loaded · parsedtarget · ready
02
Read the triplets
Owner / group / others — each is a sum of r=4, w=2, x=1.
Conversion preserves type information where the target supports it (numbers stay numeric, booleans stay boolean) so the destination parser never has to re-coerce.
tripletstype-preservinglosslesslivememoised
owner · optionsrwx · live
```
7 = r+w+x
```
options applied · liveround-trip
03
Special bits
4=setuid, 2=setgid, 1=sticky — prepended as a 4th digit.
Re-encoding is idempotent: running output back through the same converter produces the same bytes, which keeps round-trips git-friendly.
specialidempotentround-tripdiff-cleandeterministic
4755 · convertedsetuid · ready
```
rwsr-xr-x
```
converted · livediff-clean
04
Copy chmod string
Drop into a deploy script or Dockerfile.
Copy writes via navigator.clipboard.writeText; downloads use the target’s native MIME so editors apply the right syntax highlighting on open.
copyclipboardtarget MIMEblobclient-side
✓ · copiedready · done
```
chmod 755 file
```
shipped · ready to shipsuccess

Pro tips

Converting between formats, safely

Pick the strictest source format

Lossy formats hide bugs. Choose JSON or YAML as your source-of-truth, convert downstream as needed.

Round-trip in CI

If your converter is idempotent, your CI can verify A → B → A equals the original. Catches subtle data loss.

Numbers vs strings differ

YAML/TOML have a number type; CSV doesn’t. Quote IDs in CSV to keep leading-zero values intact.

Watch character encoding

Source format may be Latin-1 / Windows-1252; target should be UTF-8. Convert encoding before structure.

Preserve comments where you can

YAML and TOML support comments. Don’t silently drop them — they often encode intent.

Schema-aware beats blind

Use a schema to guide conversion. Field types, required-ness, and defaults survive better with structure.

Use Cases

When to convert permissions

Sysadmin, Docker, deploy scripts, security.

chmod commands

Translate ls -l output to a chmod number. Type information survives: numbers stay numeric, booleans stay boolean, strings stay strings. The destination parser doesn't have to re-coerce, which avoids the "'true' becomes "true"" bug class.

round-trip safe

Dockerfile RUN

Lock down config files with the right octal. Run output back through the inverse converter to verify idempotent round-trips in CI. A → B → A should produce byte-identical input — if it doesn't, you've found data loss.

type-preserving

Ansible / Terraform

Map readable modes to numeric file mode strings. Comments and metadata survive where the target format supports them (YAML, TOML, HCL). The tool doesn't silently drop intent-encoded annotations, which keeps your config self-documenting.

schema-aware

Security audit

Spot world-writable (777) and setuid (4xxx) files. Pair with a schema (JSON Schema, OpenAPI, Zod, Pydantic) to catch shape drift on either side. Catch breaking changes at conversion time rather than at runtime in production.

lossless

Onboarding

Teach new devs what rwxr-xr-x actually means. Output respects target-format conventions: quoting in CSV, indent in YAML, brackets in JSON. Existing parsers don't need patches, and the result drops into legacy pipelines unchanged.

diff-clean

Cross-platform deploy

Stay consistent across Linux distros. Encoding-aware: handles UTF-8 vs UTF-16 vs Latin-1 / Windows-1252 transparently. The character-set surprise that breaks "works on my machine" doesn't apply here.

spec-grade

FAQ

Frequently asked questions

What is 4755 for?

4 is the setuid bit — the program runs with the file owner's privileges. Combined with 755 you get the usual passwd-style binary.

What about uppercase S / T?

Uppercase means the setuid/sticky bit is set but the underlying execute bit is not — usually a misconfiguration.

Difference between 644 and 755?

644 is read+write for owner, read-only for group/others — typical for text files. 755 adds execute — typical for directories and scripts.

Why is 777 dangerous?

Anyone can read, write or execute. Almost always a misconfiguration.

Is anything sent to a server?

No. Conversion runs locally in your browser.

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