Unix Permissions Calculator

755 (rwxr-xr-x)

How it works

• Read the special-digit (setuid/setgid/sticky) and the three rwx triplets.
• Converted each triplet between its octal value (0–7) and its `rwx` symbols.
• Owner rwx, group r-x, other r-x.

• Octal is base-8: 4 = read, 2 = write, 1 = execute, summed per class (owner/group/other).
• The optional leading digit carries setuid (4), setgid (2) and sticky (1); a symbolic `s`/`t` replaces the execute marker in the display.

Methodology

1. Detect an octal (3–4 digits) or symbolic mode.
2. Convert each rwx triplet to or from its 0–7 octal value.
3. Map the optional leading digit to setuid/setgid/sticky and report every class.

Usage

1. Enter an octal mode such as 755 or a symbolic mode such as rwxr-xr-x.
2. Read the equivalent octal and symbolic forms.
3. Check the special-flag and per-class breakdown.

Examples

These are examples, not current values: they use fixed inputs, while the interactive tool computes live results in your browser.

Standard executable file

{
  "mode": "755"
}

Symbolic read-only

{
  "mode": "r--r--r--"
}

Setuid binary

{
  "mode": "4755"
}

Limitations

Reading a mode

A Unix mode is three permission triplets (owner, group, other), each an octal digit from 0 to 7 built from read (4), write (2) and execute (1). `755` is `rwxr-xr-x`: the owner can do everything, everyone else can read and traverse.

An optional fourth digit carries setuid (4), setgid (2) and sticky (1). These change execution privileges or directory deletion rules and are worth auditing on any shared system.