chmod 664 explained (rw-rw-r--)

chmod 664 sets the permissions to rw-rw-r--.

• Owner: read, write
• Group: read, write
• Others: read

When to use it

Shared files that a group collaborates on.

Security note

Others can read it. Use 660 if the content is not meant for everyone.

Tip: applying it to files and directories separately

Directories need the execute bit to be entered, files usually do not. Set them separately: find dir -type d -exec chmod 755 {} + and find dir -type f -exec chmod 644 {} +.

Other common modes