解决方案
我们可以使用 accsupp 包来实现，具体代码如下：


\documentclass{article}
\usepackage{xcolor}% http://ctan.org/pkg/xcolor
\usepackage{listings}% http://ctan.org/pkg/listings
\usepackage{accsupp}% http://ctan.org/pkg/accsupp
\renewcommand{\thelstnumber}{% Line number printing mechanism
\protect\BeginAccSupp{ActualText={}}\arabic{lstnumber}\protect\EndAccSupp{}%
}
\lstset
{
language={[LaTeX]TeX},
numbers=left,
numbersep=1em,
numberstyle=\tiny,
frame=single,
framesep=\fboxsep,
framerule=\fboxrule,
rulecolor=\color{red},
xleftmargin=\dimexpr\fboxsep+\fboxrule\relax,
xrightmargin=\dimexpr\fboxsep+\fboxrule\relax,
breaklines=true,
basicstyle=\small\tt,
keywordstyle=\color{blue},
commentstyle=\color[rgb]{0.13,0.54,0.13},
backgroundcolor=\color{yellow!10},
tabsize=2,
columns=flexible,
morekeywords={maketitle},
}

\begin{document}

\begin{lstlisting}
\documentclass{article}
\usepackage{listings}
\title{Sample Document}
\author{John Smith}
\date{\today}
\begin{document}
\maketitle
Hello World!
% This is a comment.

\end{document}
\end{lstlisting}

\end{document}

需要说明的是，这一效果适用于Adobe Reader PDF阅读器，sumatraPDF不适用，其他阅读器还未测试。
选自：http://tex.stackexchange.com/questions/30783/how-to-make-text-copy-in-pdf-previewers-ignore-lineno-line-numbers

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Thanks for sharing