Underlined links with hyperref possible?

Question

How can I have underlined links with hyperref?

That means how to configure hyperref not to change the color of the printout but use underlined active links which are completely transparent in print.

The condition for an answer to be qualified would be not to make code changes in a local copy of the hyperref macros, working for linebraking/hyphenation of links in dvi/PS as well as PDF output, configuration for different dvi-drivers (e.g. pstricks.con). Options to specify underline color, linewidth, relative position/offset to baseline are a plus but functional not essential.

Answer 1

You can try this:

\documentclass{article}
\usepackage[colorlinks=false,
            allbordercolors={0 0 0},
            pdfborderstyle={/S/U/W 1}]{hyperref}

\begin{document}

\url{blub.blub.blub}

\end{document}

Answer 2

Underline URLs, citations, figures and section references:

\usepackage[pdfborderstyle={/S/U/W 1}]{hyperref}

Or, if creating a template document:

\usepackage[hidelinks]{hyperref} % Clickable URLs and cross-references.
\hypersetup{pdfborderstyle={/S/U/W 1}} % Underline links (non-printing).
% Comment out the line above to remove underlines from links.

Notes:

• The link text is not coloured, only the underline is coloured.
• Colour of underline depends on the type of link. (i.e. different colours for URLs, citations, figures etc.)
• Underline is invisible when printed.

Edit: You can change the link underline colours like this:[1]

\usepackage{xcolor}            % specify colors by name (e.g. "red")
\usepackage{hyperref}          % clickable URls and cross-references
\hypersetup{
    pdfborderstyle={/S/U/W 1}, % underline links instead of boxes
    linkbordercolor=red,       % color of internal links
    citebordercolor=green,     % color of links to bibliography
    filebordercolor=magenta,   % color of file links
    urlbordercolor=cyan        % color of external links
}

There are many more customisation options. See [1].

See this answer if you want URLs to look like they do in a web browser.