chmod 644 explained (rw-r--r--)

chmod 644 sets the permissions to rw-r--r--.

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

When to use it

The standard for regular files: web pages, config files and documents.

Security note

Anyone can read it, so do not use it for secrets or private keys.

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