Click checkboxes to set Unix/Linux file permissions — get the octal code and chmod command instantly.
| Entity | Read (r) | Write (w) | Execute (x) | Octal |
|---|---|---|---|---|
| Owner The file's owner | 0 | |||
| Group Users in the file's group | 0 | |||
| Others Everyone else | 0 |
chmod command.Unix and Linux file permissions control who can read, write, or execute a file. Each file has three sets of permissions: for the owner, the group, and others (everyone else). Each set is represented by three bits — read (4), write (2), and execute (1) — which are summed to produce a single digit. Three digits together form the octal code, e.g. 755 means owner has 7 (4+2+1 = rwx), group has 5 (4+1 = r-x), and others have 5 (r-x). The symbolic notation uses letters (r, w, x, -) in the format used by ls -l. All calculation happens locally in your browser — nothing is sent to any server.
chmod 755 sets permissions to rwxr-xr-x. The owner can read, write, and execute the file. The group and others can only read and execute it (not write). This is the standard permission for web server scripts, public executables, and directories you want everyone to traverse.
Both describe the same permissions in different formats. Octal notation uses three digits (e.g. 755), where each digit is the sum of enabled bits (read=4, write=2, execute=1). Symbolic notation uses a 9-character string like rwxr-xr-x, showing explicit letters for enabled permissions and - for disabled ones. The chmod command accepts both formats.
777 gives all users — including those not on your system who access the file via a web server or shared service — full read, write, and execute access. Any process on the system can modify or delete the file. For web-accessible files this creates a serious security risk, as a compromised web process could overwrite or execute arbitrary content. Use the minimum permissions necessary for your use case.