\ProvidesPackage{di/linenumber}
\RequirePackage[pagewise,modulo]{lineno}

\def\linenumberfont{\normalfont\footnotesize\sffamily}
\linenumbers

% A fix for compatibility between lineno and amsmath.
% http://simon.bonners.ca/blog///blog5.php/line-number-and-amsmath
% http://phaseportrait.blogspot.nl/2007/08/lineno-and-amsmath-compatibility.html
% https://groups.google.com/forum/#!msg/comp.text.tex/9Oti-kwXXgs/ts_VLUCaa2gJ
\newcommand*\patchAmsMathEnvironmentForLineno[1]{%
    \expandafter\let\csname old#1\expandafter\endcsname\csname #1\endcsname
    \expandafter\let\csname oldend#1\expandafter\endcsname\csname end#1\endcsname
    \renewenvironment{#1}%
    {\linenomath\csname old#1\endcsname}%
    {\csname oldend#1\endcsname\endlinenomath}}% 
\newcommand*\patchBothAmsMathEnvironmentsForLineno[1]{%
    \patchAmsMathEnvironmentForLineno{#1}%
    \patchAmsMathEnvironmentForLineno{#1*}}%
\AtBeginDocument{%
    \patchBothAmsMathEnvironmentsForLineno{equation}%
    \patchBothAmsMathEnvironmentsForLineno{align}%
    \patchBothAmsMathEnvironmentsForLineno{flalign}%
    \patchBothAmsMathEnvironmentsForLineno{alignat}%
    \patchBothAmsMathEnvironmentsForLineno{gather}%
    \patchBothAmsMathEnvironmentsForLineno{multline}%
}