chmod 664 — what rw-rw-r-- means
664
rw-rw-r--
The owner and group can read and write; others can read only.
Note: this grants group or shared write access — fine for team directories, but make sure that is what you intend.
Permission breakdown
When to use 664
Shared files a team edits together — documents or data owned by a group where any member updates them, while the rest of the system reads but can't change.
Set it with chmod
Apply this permission to a file:
chmod 664 filenameOr apply it recursively to a directory and everything inside it:
chmod -R 664 directory/Other common permissions
Or build any permission with the interactive chmod calculator.