chmod 660 — rw-rw----

What chmod 660 allows, when to use it, and the calculator pre-filled with it — toggle any box to compare.

660
rw-rw----
Owner6
rw-
Group6
rw-
Others0
---
Special bits
chmod 660 filename
chmod -R 660 /path/to/dir

What this means

Owner can read, write. Group can read, write. Others has no permissions.

What chmod 660 allows

WhoReadWriteExecute
Owner✓✓—
Group✓✓—
Others———

Files the owner and group both read and write, hidden from everyone else — shared sockets, logs or data files of a service group.

Commands

chmod 660 fileset it on one file or directory
chmod u=rw,g=rw,o= filethe same thing in symbolic form
chmod -R 660 dir/recursively — careful: it applies to files and directories alike
ls -l filecheck the result: -rw-rw---- (a directory shows drw-rw----)

On a directory, read lets you list it, write lets you create and delete entries, and execute lets you enter it and open what's inside. That's why directories usually get 755 or 750 while files get 644 or 640.

Frequently asked

What does chmod 660 mean?

Owner: read, write. Group: read, write. Others: no access. In ls -l it shows as rw-rw----.

What is the symbolic form of chmod 660?

chmod u=rw,g=rw,o= file — it sets exactly the same permissions as chmod 660.

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Common chmod permissions explained

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