\usepackage[switch,mathlines,displaymath]{lineno}
%\runninglinenumbers %% for continous line numbering regardless of box and minipage but only on left side in single/double column
\linenumbers %% properly in single/double column but boxes and minipage linenos not getting continuous

\def\linenumberfont{\usefont{T1}{ptm}{m}{n}\color{red}\fontsize{8}{10}\selectfont}
\if@twocolumn
\setlength\marginparwidth{.75cm}
\setlength\marginparsep{19.5\p@}
\else
\setlength\marginparwidth{20pt}
\setlength\marginparsep{24pt}
\fi
\newcommand\linenomathWithnumbersforams{%
  \ifLineNumbers
  %\ifx\@@par\@@@par\else
    \ifnum\interlinepenalty>-\linenopenaltypar
      \global\holdinginserts\thr@@
      \advance\interlinepenalty \linenopenalty
     \ifhmode                                   % v4.3
      \advance\predisplaypenalty \linenopenalty
     \fi
      %\advance\postdisplaypenalty \linenopenalty
      \advance\interdisplaylinepenalty \linenopenalty
    \fi
  \fi
  \ignorespaces
  }

\newcommand\linenomathWithnumbersformultline{%
  \ifLineNumbers
  %\ifx\@@par\@@@par\else
    \ifnum\interlinepenalty>-\linenopenaltypar
      \global\holdinginserts\thr@@
      \advance\interlinepenalty \linenopenalty
     \ifhmode                                   % v4.3
      %\advance\predisplaypenalty \linenopenalty
     \fi
      %\advance\postdisplaypenalty \linenopenalty
      \advance\interdisplaylinepenalty \linenopenalty
    \fi
  \fi
  \ignorespaces
  }



\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}%
{\def\linenomath{\linenomathWithnumbersforams}%added
 \@namedef{linenomath*}{\linenomathNonumbers}%added
\linenomath\csname old#1\endcsname}%
{\csname oldend#1\endcsname\endlinenomath}}%
\newcommand*\patchBothAmsMathEnvironmentsForLineno[1]{%
\patchAmsMathEnvironmentForLineno{#1}%
\patchAmsMathEnvironmentForLineno{#1*}%
}%

\AtBeginDocument{%
\patchBothAmsMathEnvironmentsForLineno{equation}% deleted
\patchBothAmsMathEnvironmentsForLineno{align}%
\patchBothAmsMathEnvironmentsForLineno{flalign}%
\patchBothAmsMathEnvironmentsForLineno{alignat}%
\patchBothAmsMathEnvironmentsForLineno{gather}%
%\patchBothAmsMathEnvironmentsForLineno{multline}%
%\patchBothAmsMathEnvironmentsForLineno{split}%
\patchAmsMathEnvironmentForLineno{array}%
%\patchAmsMathEnvironmentForLineno{split}%
}

%%\AtBeginDocument{%
  \let\LN@align\align
  \let\LN@endalign\endalign
  \renewenvironment{align}%
     {\linenomath\LN@align}%
     {\LN@endalign\endlinenomath}%
%%}


\renewenvironment{multline}{\linenomathWithnumbersformultline%
  \start@multline\st@rredfalse
}{%
  \iftagsleft@ \@xp\lendmultline@ \else \@xp\rendmultline@ \fi
  \ignorespacesafterend
\endlinenomath}
\renewenvironment{multline*}{\linenomathWithnumbersformultline\start@multline\st@rredtrue}{\endmultline\endlinenomath}

\def\insplit@{%
  \global\setbox\z@\vbox\bgroup
    \Let@ \chardef\dspbrk@context\@ne \restore@math@cr
    \default@tag % disallow use of \tag here
    \ialign\bgroup
      \hfil%
      \strut@
       $\m@th\displaystyle{##}$% 
     &$\m@th\displaystyle{{}##}$%
      \hfill % Why not \hfil?---dmj, 1994/12/28
      \crcr\noalign{\global\advance\c@linenumber\@ne}%
}

\endinput