Chmod Calculator
Guide: Linux File Permissions and chmod Explained
| Read (4) | Write (2) | Execute (1) | |
|---|---|---|---|
| Owner | |||
| Group | |||
| Everyone else |
chmod 755 filename- Owner: read, write, execute
- Group: read, execute
- Everyone else: read, execute
Nothing you enter or choose here leaves your device. This tool runs in your browser.
How to use
- 1Tick the permissions for owner, group and everyone else.
- 2Read the octal value, such as 755, and the symbolic form, such as rwxr-xr-x.
- 3Or type an octal or symbolic value to see the boxes change.
- 4Click Copy command.
Frequently asked questions
How does the octal number work?
Read is 4, write is 2 and execute is 1. Add them up for each of owner, group and others, so rwx is 7, r-x is 5 and r-- is 4. That gives 755 for rwxr-xr-x.
What permissions should I use?
644 for ordinary files, 755 for folders and programs, 600 for private files such as SSH keys and 700 for private folders. Avoid 777, which lets anyone change the file.
What are setuid, setgid and the sticky bit?
They are special bits shown as a fourth digit. Setuid and setgid run a program with the owner's or group's rights, and the sticky bit on a folder, like /tmp, lets only the owner delete their own files.
What does execute mean on a folder?
It lets you enter the folder and reach the files inside it. Without it you can't open the files even if you can list them.
Read the guides
Learn how this works and how to get the most from it.
Developer
Linux File Permissions and chmod Explained
Understand read, write and execute permissions, what 755 and 644 mean, and how to use chmod with octal and symbolic modes.
2 min read
Developer
Subnet Masks and CIDR Notation Explained
What /24 and 255.255.255.0 mean, how to count hosts in a subnet, and how to split a network into smaller ones.
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