What is the LaTeX command for “em dash” (—)?

I am trying to insert the symbol in the title of the question, which I copied from a PDF article, but it appears as space in the output file. What is the corresponding LaTeX command?

-
@HarishKumar: The symbol is an em dash. – Thorsten Donig Apr 26 '12 at 10:39
O my god! I was expecting something else after the emdash as the OP said it appears as space. – Harish Kumar Apr 26 '12 at 10:44
Probably the input encoding does not have the em dash configured. I'd suggest to use the solution by Keks Dose. – topskip Apr 26 '12 at 10:58
Also see How to look up a symbol? – Caramdir Apr 26 '12 at 20:51
If my typographer's memory serves me, the first item in the list above is not known as a hyphen but as a tee dash. (Or was it simply a matter of tee spaces, en spaces, and em spaces?) Gosh, I used to all know this back when I did actual physical typography... – John Laudun Jan 9 at 3:45

The LaTeX command for such a line are three small ones: `---`

-
Alternatively `\textemdash`. – Torbjørn T. Apr 26 '12 at 15:20
Or use Xe/LuaLaTeX and just type `—`. – Caramdir Apr 26 '12 at 20:48
@Caramdir: You don't even have to use Xe/LuaLaTeX; pdfLaTeX with `\usepackage[utf8]{inputenc}\usepackage[T1]{fontenc}` works fine for directly inputting an em dash `—`. – doncherry Apr 28 '12 at 9:54
This is not a LaTeX command and it doesn't work universally: scripts.sil.org/cms/scripts/page.php?item_id=xetex_faq#ligs – Roman Cheplyaka Feb 14 at 9:41
@RomanCheplyaka Yes, you are right, it's not a LaTeX command. But in ten years of using LaTeX it never failed, so thank you for your comment, but for most of the readers the answer contains what they need, doesn't it? – Keks Dose Feb 14 at 11:22

• Hyphen: `-`
• En-dash: `--`
• Em-dash: `---`
To avoid misunderstandings, I like to call the first one (`-`) a hyphen, because it's usually not used as a dash. In Unicode it's called Minus-hyphen, that's the one normal keyboards enter. (Unicode also has a symbol called Hyphen‌​. – doncherry May 1 '12 at 13:13