Chmod Calculator
Calculate Unix file permissions with a visual editor. Convert between numeric (755) and symbolic (rwxr-xr-x) formats instantly.
| Read (4) | Write (2) | Execute (1) | Octal | |
|---|---|---|---|---|
| owner | 7 | |||
| group | 5 | |||
| others | 5 |
Permission
755
-rwxr-xr-x
chmod 755 filename
Common Permissions
Unix File Permissions Made Simple
Unix file permissions control who can read, write, and execute files and directories. The three-digit octal system (like 755 or 644) encodes permissions for the owner, group, and others. Each digit is the sum of read (4), write (2), and execute (1) permissions.
Common Permission Patterns
755 is the standard for web-accessible directories and executable scripts. 644 is the default for regular files — owner can edit, everyone else can read. 600 is for private files like SSH keys and configuration files containing secrets. Never use 777 in production — it gives everyone full access.
Frequently Asked Questions
What does chmod do?
chmod (change mode) sets file access permissions on Unix/Linux systems, controlling who can read, write, or execute a file.
What does 755 mean?
755 means the owner can read, write, and execute (7), while group members and others can only read and execute (5). This is the standard permission for web directories.
What is the most secure permission for private files?
600 restricts access to the file owner only (read and write). Use 700 for private directories that need execute permission for traversal.
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