I'm using the hyperref package in my document to provide hyperlinks to external documents. However, I don't want to have the links coloured or underlined, because I find this usually ugly and distracting. What I would rather like is a little symbol beside the link text to provide a small hint for the reader that there is something clickable. What I have in mind is something like the little symbol constisting of a small square and an arrow you can find e.g. in Wikipedia for external links. Is there any package or font that provides such a symbol or do I have to brew one myself?

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Have a look at symbols_a4.pdf if you can find a suitable symbol and define your own command which prints the symbol and the hyperlink. If you don't find a symbol you need to define your own symbol, e.g. with TikZ. –  Uwe Ziegenhagen Feb 22 '13 at 16:43

If you already set a document with a lot of \hrefin it, you also can redefine the hrefcommand by copying the original macro to a new one with \let (works here, but not in every case!), see my example.

Note, that I used a dedicated hyperref option for hiding the links. I also show some symbols from two dingbat fonts. Fonts of this type should be in general the most useful for your need.

\documentclass{article}

\usepackage{bbding,pifont} % two dingbat fonts

\usepackage{graphicx} % "graphics" would be enough for the minimal example

% Redefinition:
\let\orighref\href
\renewcommand{\href}[2]{\orighref{#1}{#2}\,\ArrowBoldUpRight} %bbding
% the same with symbol included in link:
% \renewcommand{\href}[2]{\orighref{#1}{#2\,\ArrowBoldUpRight}}

% Examples:
\newcommand{\hrefa}[1]{\orighref{http://example.com/}{#1}\,\scalebox{0.75}{\ArrowBoldUpRight}} %bbding
\newcommand{\hrefb}[1]{\orighref{http://example.com/}{#1}\,\ding{230}} %pifont
\newcommand{\hrefc}[1]{\raisebox{-0.4ex}{\HandRight}\,\orighref{http://example.com/}{#1}} %bbding
\newcommand{\hrefd}[1]{\scalebox{1.3}{\raisebox{-0.3ex}{\ding{43}}}\,\orighref{http://example.com/}{#1}} %pifont
\newcommand{\hrefe}[1]{\scalebox{0.8}{\raisebox{-0.5ex}{\HandRightUp}}\,\orighref{http://example.com/}{#1}} %bbding
\newcommand{\hreff}[1]{\ding{226}\,\orighref{http://example.com/}{#1}} %pifont
\newcommand{\hrefg}[1]{\ding{238}\,\orighref{http://example.com/}{#1}} %pifont
% the last with symbol included in link:
% \newcommand{\hrefg}[1]{\orighref{http://example.com/}{\ding{238}\,#1}} %pifont

\begin{document}

\end{document}


Update:

Bad timing – shortly after writing of this answer a new package fontawesome was released. For Xe(La)TeX or Lua(La)TeX users this package “grants access to 249 web-related icons provided by the included Font Awesome free font” (cite from documentation abstract). One of them is the symbol for external links accessible with \faicon{external-link} or \faExternalLink:

% Compile with LuaLaTeX or XeLaTeX
\documentclass{article}
\usepackage{fontawesome}

% Redefinition, symbol included in link:
\let\orighref\href

\begin{document}
\href{http://example.com}{example web site}
\end{document}


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Maybe thw following is useful.

Code

\documentclass{article}

\usepackage{bbding}
\usepackage[pdfborder={0 0 0}]{hyperref}

\href{#1}{#2}\,\raisebox{-1pt}{\footnotesize\FourStarOpen}%
}

\begin{document}

Click \link{http://www.latex-project.org/}{here} to go to the webpage.

\end{document}


or

\documentclass{article}

\usepackage{bbding}
\usepackage[pdfborder={0 0 0}]{hyperref}

\href{#1}{#2}\,{\scriptsize\FourStarOpen}%
}

\begin{document}

Click \link{http://www.latex-project.org/}{here} to go to the webpage.

\end{document}


Output (for the first MWE)

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Another idea:

\documentclass{standalone}
\usepackage{txfonts}
\usepackage{graphicx}
\def\xLink{$\!\vcenter{\hbox{\rotatebox{45}{$\DiamondRight$}}}\!\!$}
\begin{document}