How does one insert a backslash or a tilde (~) into LaTeX?

Question

• How does one insert a "\" (backslash) into the text of a LaTeX document?
• And how does one insert a "~" (tilde)? (If you insert \~, it will give you a tilde as an accent over the following letter.)

I believe \backslash may be used in math formulae, but not into text itself. Lamport's, Kopka's, and Mittelbach's texts have said as much (but no more), and so left me hanging on how to get a backslash into regular text.

Answer 1

TL;DR

\textbackslash produces a backslash in text-mode. The math-mode $\sim$ and \texttildelow (from textcomp package) are options for a lower tilde (while \~{} and \textasciitilde produce a raised tilde in text-mode)

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Long Answer:

The Comprehensive LaTeX Symbol List is your friend. The correct link seems to keep changing, but if you have a complete TeX Live installation, the command texdoc symbols-a4 will display your local copy.

\textbackslash and \textasciitilde are found in several places in the document, but the LaTeX 2e ASCII Table (Table 529 as of this writing) and the following discussion are a convenient resource for all ASCII characters. In particular, the discussion notes that \~{} and \textasciitilde produce a raised tilde, whilst the math-mode $\sim$ and \texttildelow are options for a lower tilde; the latter is in the textcomp package, and looks best in fonts other than Computer Modern. If you are typesetting file names or urls, the document recommends the url package.

Remember to delimit TeX macros from surrounding text, e.g. bar\textasciitilde{}foo.

Answer 2

Canonical answer

There’s now an extensive discussion with a canonical answer on this website. Use the solution described there. tl;dr:

For a URL or file path, use url (or hyperref). Otherwise:

1. If you are using the standard Computer Modern font, txfonts or pxfonts: use this workaround:

    \usepackage{textcomp}
    \newcommand{\textapprox}{\raisebox{0.5ex}{\texttildelow}}
   

   … or use Latin Modern fonts instead (see next point).

2. If you are using a PostScript/Type1 font via a package such as mathptmx or lm: Set the font encoding to T1 (via \usepackage[T1]{fontenc}) and use \textasciitilde.

3. If you are using a TTF or OTF font via XeTeX or LuaTeX: Use \char`~ to insert a tilde.

Obsolete answer, preserved for posterity

textcomp’s \texttildelow is actually quite a bad choice: it’s too low for most fonts.

A much better rendering can be achieved by the following, which tweaks the appearance of the (otherwise too wide) $\sim$:

{\raise.17ex\hbox{$\scriptstyle\sim$}}

This was taken from the Arbitrary LateX reference … the page also provides a good comparison sheet:

When used in \texttt, I would add a \mathtt around the tilde, to make it fit the font better:

{\raise.17ex\hbox{$\scriptstyle\mathtt{\sim}$}}

The difference is small but noticeable.

Answer 3

You can also use the "plain TeX" method of indexing the actual ascii character in the current font:

\char`\\
\char`\~

I often use the former for writing macros that need the backslash in the typewriter font; \textbackslash will sometimes still use the roman font depending on the font setup. Of course, if you're using these a lot you should define your own macro for them:

\newcommand\SLASH{\char`\\}

Answer 4

I occurs to me that you might be trying to type URLs. In that case, the url package takes care of everything for you:

\usepackage{url}
...
\url{somewhere\home\~will}

For paths (i.e., local files), there is \path, working the same way as \url, just providing the correct links in case hyperref is loaded.

If you are loading hyperref there is no reason to load url as well.

Answer 5

Well if that isn't annoying:

 \textbackslash
 \texttt{\char`\~} or $\sim$

Answer 6

Hmm; \textbackslash (mentioned by others) isn't in my reference book (Kopka and Daly).

At any rate, math mode provides \sim, \backslash, and \setminus (the latter two appear to look the same and differ only by spacing in math mode).

My LaTeX book – which, as you would expect, features the \ extensively – seems to use the verbatim environment. For example, this code:

\begin{verbatim}
 \addtocounter{footnote}{-1}\footnotetext{Small insects}
 \stepcounter{footnote}\footnoteext{Large mammals}
\end{verbatim}

Produces this text in the book:

 \addtocounter{footnote}{-1}\footnotetext{Small insects}
 \stepcounter{footnote}\footnoteext{Large mammals}

The \verb command is similar, but the argument must be on one line only. The first character after the b is the delimiter; for example:

\verb=\emph{stuff}=

will produce

\emph{stuff}

So you could presumably get your backslash by typing:

\verb=\=

You can also add a * – i.e. \verb* or \begin{verbatim*} – to make whitespace visible.

It is interesting to speculate how you would get an example of a verbatim environment into a document.. (using \verb to do the last line, I guess)

Answer 7

For the tilde, you can use empty curly brace pair. That puts the "over the letter" tilde over an "empty" letter, so it's placed upward.

My tilde\~{}here

Answer 8

From https://faculty.math.illinois.edu/~hildebr/tex/bibliographies.html

"... tilde symbol (~), which without special coding gets interpreted as a blank space, and therefore needs to be escaped by a backslash (\~) or replaced by the math "twiddle" symbol $\sim$. Fortunately, there is a package, url, that provides a painless way to typeset URL's. To use this package available, add

\usepackage{url}

near the beginning of the document, and enclose any web and email addresses in the document in \url{...}:

\url{http://www.math.drofnats.edu/~gauss}
\url{gauss@math.drofnats.edu}

..."

I hope this could help you in typewriting a regular tilde character.

Answer 9

Personally, I learned more actually changing the catcodes myself :)

\begingroup
  \catcode `~=11
  \gdef\mytilde{~}
  \catcode `\|=0
  \catcode `\\=11
  |gdef|mybs{\}
|endgroup

and then something like

This is a tilde: \mytilde
This is a backslash: \mybs

Answer 10

$\sim$ works for me in Plain TeX.

Eg. ~70 can be rendered as

$\sim$70