Unix CHMOD Calculator

Calculate octal and symbolic file permissions visually.

Drop a file or click to open
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Owner
Group
Others
Octal Notation 000
Symbolic Notation ---------
Shell Script

Common Presets

Files (644)

Owner can read/write, group and others can read. Standard for most files.

Apply Preset

Directories (755)

Owner has full access, group and others can read and execute. Standard for directories.

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Private (700)

Only the owner can read, write, or execute. No access for group or others.

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Public (777)

Everyone has full read, write, and execute permissions. Use with caution.

Apply Preset

Understanding CHMOD

CHMOD (Change Mode) is a fundamental command in Unix-like operating systems that defines who can read, write, or execute a file or directory.

Permissions are divided into three tiers: Owner (the user who created the file), Group (a collection of users), and Others (everyone else).

Octal vs Symbolic

  • Octal (Numeric): Uses three digits (0-7) to represent permissions (e.g., 755).
  • Symbolic: Uses a 10-character string like -rwxr-xr-x.
  • Calculations: Read = 4, Write = 2, Execute = 1. Add them up for each tier.