-- Explained

--, a string of two hyphen-minus characters, may approximate or refer to:

• En dash (–)
• Em dash (—), as a typewriter approximation
• Sig dashes (--), the email and Usenet signature delimiter
• For Unix commands, used as a prefix for command options. By itself, it typically means the end of command options.
• The decrement operator in some programming languages
• Inline comments in some programming languages

See also

• Double hyphen (one above the other)
• - (disambiguation)
• HTML comment tag, <nowiki><!--</nowiki> and <nowiki>--></nowiki>
• Horizontal rule, which is represented by ---- in MediaWiki markup