Latex glossaries: Hyperref/Link only the first occurance of an entry in each section?

While you can manually renounce the hyperlink by using \glsentrytext{entry}, or \glsentryname{entry}, or \gls*{entry} instead of \gls{entry}, this is cumbersome, as one would have to track the place of the first usage oneself.

An automatic approach is to patch \@gls@:

\documentclass[a4paper,10pt]{article}

\usepackage[colorlinks]{hyperref}
\usepackage{glossaries}

\usepackage{etoolbox}
\makeatletter
%% patch first occurence of "\@gls@link[#1]{#2}{\@glo@text}", as this is the one for \glsused{#2}
\patchcmd{\@gls@}
  {\@gls@link[#1]{#2}{\@glo@text}}
  {\@gls@link[#1,hyper=false]{#2}{\@glo@text}}
  {}{}
\makeatother


\makeglossaries
\newglossaryentry{pear}{
  name=pear,
  description={an oddly shaped fruit}
}

\begin{document}
\gls{pear}, \gls{pear}, \gls{pear}, \gls{pear}.

\printglossaries
\end{document}

If you also use upper case variants \Gls and \GLS, the respective internal macros \@Gls@ and \@GLS@ need similar patching:

\patchcmd{\@Gls@}
  {\@gls@link[#1]{#2}}
  {\@gls@link[#1,hyper=false]{#2}}
  {}{}

\patchcmd{\@GLS@}
  {\@gls@link[#1]{#2}{\MakeUppercase{\@glo@text}}}
  {\@gls@link[#1,hyper=false]{#2}{\MakeUppercase{\@glo@text}}}
  {}{}

There's a hook \glslinkcheckfirsthyperhook that gets used by commands like \gls. It's original purpose was to assist with the opposite (don't hyperlink on first use) but it also can be used in this situation:

\documentclass{article}

\usepackage[colorlinks]{hyperref}
\usepackage{glossaries}

\makeglossaries

\renewcommand*{\glslinkcheckfirsthyperhook}{%
  \ifglsused{\glslabel}%
  {%
    \setkeys{glslink}{hyper=false}%
  }%
  {}%
}

\newglossaryentry{sample}{name={sample},description={an example}}
\newglossaryentry{sample2}{name={another sample},description={another example}}

\begin{document}

First use: \gls{sample}, \gls{sample2}.

Next use: \gls{sample}, \gls{sample2}.

\printglossaries

\end{document}

This produces:

Edit: This works for all the \gls-like commands that query the first use flag (e.g. \Gls and \glsdisp). It doesn't work for the \glstext-like commands that don't query the first use flag (e.g. \glstext and \glslink).