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Chmod 770

chmod 770 sets the permissions to rwxrwx---: it gives the owner and group full access, and others nothing. Here is exactly what that allows on files and directories, when to use it, and the commands to apply it.

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ClassreadwriteexecuteValue
owner7
group7
others0
Common:
$ chmod 770 file.sh
$ chmod u=rwx,g=rwx,o= file.sh
  • • The owner can read, write and execute.
  • • The group can read, write and execute.
  • • Everyone else can do nothing.

What chmod 770 means

WhoDigitLettersOn a fileOn a directory
owner 7 rwx Can read, modify and run Can list files, create, delete and rename files and enter it and open files
group 7 rwx Can read, modify and run Can list files, create, delete and rename files and enter it and open files
others 0 --- No access No access

Each digit is the sum of read (4), write (2) and execute (1). In ls -l output it looks like this: 

$ ls -l
drwxrwx---  2 alice  staff  4096 Oct 21 10:30 example-dir
  • The owner can read, write and execute.
  • The group can read, write and execute.
  • Everyone else can do nothing.

When to use 770

  • Private team directories
  • Application data shared by a service and its admins

770 is the private version of 775: the owner and group can do everything, and other users can’t even list the directory. It is a good default for data that a service account and an admin group both manage, such as /var/lib/myapp.

770 is also the default mode for new directories, with umask 007.

Is chmod 770 safe?

Yes. Nobody outside the owner and group can access it at all (except root).

Commands

# One file or directory
chmod 770 path

# Same thing in symbolic form
chmod u=rwx,g=rwx,o= path

# Every directory under a tree (leaves files alone)
find /path/to/dir -type d -exec chmod 770 {} +

# Check the result
stat -c '%a %A %n' path    # Linux
stat -f '%Lp %Sp %N' path  # macOS

Avoid chmod -R 770 on a whole tree: it gives files and directories the same mode. The find form above changes only directories.

Compare with similar modes

ModeSymbolicDifference
777 rwxrwxrwx Gives everyone full read, write and execute access
775 rwxrwxr-x Gives the owner and group full access, and others read and execute
750 rwxr-x--- Gives the owner full access, the group read and execute, and others nothing
700 rwx------ Gives the owner full access and everyone else nothing

Other chmod values

777 · 775 · 755 · 751 · 750 · 744 · 711 · 700 · 666 · 664 · 660 · 644 · 640 · 600 · 555 · 500 · 444 · 400 · 000 · 1777 · 2775 · 4755

Need a different combination? Use the Chmod Calculator.

Sources

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Frequently asked questions

What does chmod 770 mean?

chmod 770 sets the permissions to rwxrwx---. The owner can read, write and execute. The group can read, write and execute. Everyone else can do nothing.

Is chmod 770 safe?

Yes. Nobody outside the owner and group can access it at all (except root).