Chmod Calculator
Visualize and calculate Linux file permissions.
What is this Tool?
Chmod Calculator is a visual utility for Linux/Unix administrators and developers. It translates file system permissions between their numerical (Octal, e.g., 755) and textual (Symbolic, e.g., -rwxr-xr-x) representations.
Instead of mentally adding 4+2+1 for every file, simply click the checkboxes to grant or revoke Read, Write, and Execute permissions. The tool instantly generates the correct `chmod` command for you.
How to use
- Set Owner: Decide what the file owner can do (usually Read & Write).
- Set Group: Permissions for other users in the file's group (often Read-only).
- Set Public: Permissions for everyone else (often Read-only or None).
- Copy Command: Use the 'Octal' code for speed (`chmod 755 file`) or 'Symbolic' for clarity in scripts.
Why do you need it?
- Visual Learning: Understand how the permission bits (4, 2, 1) sum up to the final octal number.
- Avoid Mistakes: One wrong digit can accidentally make a private key public. Use this calculator to be 100% sure before running commands on a production server.
- Reference: Quickly check what standard permissions like 644 (Files), 755 (Directories), or 400 (Keys) actually mean.
FAQ
Q. What is 777 permission?
It gives Read, Write, and Execute access to EVERYONE. This is a massive security risk. Never use 777 unless you absolutely know why you need it.
Q. What is the difference between 644 and 755?
644 is standard for files (Owner writes, others read). 755 is standard for directories (Everyone can enter/read, only Owner can write).
Q. Do I need sudo?
If you don't own the file, yes. You will need to run `sudo chmod ...` to apply changes.