Chmod calculator
Tick the boxes, or paste an octal number or an ls -l line. Everything stays in step.
| Who | Read | Write | Execute |
|---|---|---|---|
| Owner | |||
| Group | |||
| Other |
よくある質問
What do the three digits mean?
One digit each for the owner, the group and everyone else. Each is read (4) plus write (2) plus execute (1) added together, so 7 is all three, 6 is read and write, and 5 is read and execute. That makes 755 “owner can do anything, everyone else can read and run”.
Why is there sometimes a fourth digit?
It holds the special bits: setuid (4), setgid (2) and sticky (1). They appear in the symbolic form in place of an execute letter — rwsr-xr-x has setuid. A capital S or T means the special bit is set but execute is not, which is almost always a mistake.
Is 777 ever a good idea?
Almost never. It lets any user on the machine change or replace the file, and many web servers refuse to run scripts that are writable by everyone. If something only works at 777, the real problem is usually file ownership.