--

--, a string of two hyphen-minus characters, may approximate or refer to: Em dash (—), as a typewriter approximation Sig dashes (--), the email and Usenet signature delimiter It is morse code for the letter 'M' For Unix-like operating system commands, used as a prefix for long options. By itself, it typically means the end of command options. The decrement operator in some programming languages Inline comments in some programming languages