How to Use the Unix chmod Permission Calculator
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Check the Read, Write, Execute boxes for Owner, Group, and Other.
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Or enter a numeric chmod value (e.g. 755) to decode it.
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View the symbolic representation and human-readable explanation.
Practical Example & Use Case
Common Real-World Scenario
Setting 755 (rwxr-xr-x) for an executable script — owner can read/write/execute, others can only read and execute.
Technical Notes & Limitations
Browser Engine Architecture
Covers standard UGO permissions. Special bits (setuid, setgid, sticky) shown as informational.
Frequently Asked Questions
What does chmod 777 mean?
chmod 777 gives full read/write/execute to everyone — a critical security risk on web servers.
What permissions should web files have?
Directories: 755. Files: 644. Scripts: 755. Config files with passwords: 600. Never 777 in production.