chmod 2755
chmod 2755 is rwxr-sr-x (with special bits).
What 2755 grants
| Who | Digit | Permissions | Adds up as |
|---|---|---|---|
| Owner | 7 | read, write, execute | 4 + 2 + 1 = 7 |
| Group | 5 | read, execute | 4 + 1 = 5 |
| Others | 5 | read, execute | 4 + 1 = 5 |
| Special | 2 | setgid | 2000 = 2 |
When 2755 is the right answer
Standard 755 plus setgid. On a directory, new entries inherit the directory’s group rather than the creating user’s, which keeps a shared tree consistently owned.
The command
chmod 2755 filename
chmod -R 2755 directory/Because the owner has the execute bit, this works on a directory as well as a file — on a directory, execute is what grants the right to enter it and reach the entries inside.
How it is written elsewhere
| Octal | 2755 |
| Symbolic | rwxr-sr-x |
As a file in ls -l | -rwxr-sr-x |
As a directory in ls -l | drwxr-sr-x |
| Binary | 111 101 101 |
| World-writable | No |
Frequently asked questions
What does chmod 2755 mean?
It sets owner to read, write, execute, group to read, execute, others to read, execute, with the setgid bit set. In symbolic notation that is rwxr-sr-x.
How do I apply 2755?
Run chmod 2755 filename. Add -R to apply it to a directory and everything inside, though be careful: a recursive numeric chmod marks every file the same way, which is rarely correct for a mixed tree of files and directories.
Is 2755 safe?
It grants no write access outside the owner, so it is a reasonable setting as long as the owner is the account you intend.
What is 2755 in symbolic notation?
rwxr-sr-x. Written as ls -l shows it, with a leading file-type character, an ordinary file would appear as -rwxr-sr-x and a directory as drwxr-sr-x.