Chmod Calculator
Visual file permission calculator. Convert between symbolic (rwxr-xr-x) and octal (755) notation, toggle setuid/setgid/sticky bits, and copy the chmod command.
Last updated:
| Read | Write | Execute | |
|---|---|---|---|
| Owner | |||
| Group | |||
| Other |
How to Use Chmod Calculator
- 1Click the checkboxes to set read, write, and execute permissions for owner, group, and other.
- 2See the octal value (e.g., 755), symbolic notation (e.g., rwxr-xr-x), and chmod command update in real time.
- 3Alternatively, type an octal value directly and the checkboxes update to match.
- 4Click the copy button to copy the chmod command to your clipboard.
Frequently Asked Questions
What is chmod?
chmod (change mode) is a Unix/Linux command that changes file and directory permissions. Permissions control who can read, write, or execute a file. chmod accepts both octal notation (755) and symbolic notation (u+rwx,g+rx,o+rx).
What does 755 mean?
755 means the owner has read (4) + write (2) + execute (1) = 7, while group and others have read (4) + execute (1) = 5. In symbolic form: rwxr-xr-x. This is a common permission for web directories and scripts.
What permission should I use for web files?
Directories typically use 755 (rwxr-xr-x). Regular files use 644 (rw-r--r--). Scripts need 755 (rwxr-xr-x). Sensitive configuration files should use 600 (rw-------) or 640 (rw-r-----).
What are the setuid, setgid, and sticky bits?
They are a fourth, leading octal digit. setuid (4) makes an executable run as its owner (e.g. /usr/bin/passwd). setgid (2) makes files inherit the directory group, or runs an executable as its group. The sticky bit (1) on a shared directory like /tmp lets only a file's owner delete it. In symbolic notation they appear as s/S in the owner/group execute slot and t/T in the other slot — uppercase when the underlying execute bit is off.
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