% engine=luatex

\starttext

\startbuffer[demo]
\startlinenumbering
    \input ward
    \startcolumns
        \input tufte
    \stopcolumns
    \input ward
\stoplinenumbering
\stopbuffer

\startbuffer[setup]
\setuplinenumbering[align=middle]
\stopbuffer
\getbuffer[demo,setup] \page

\startbuffer[setup]
\setuplinenumbering[align=left]
\stopbuffer
\getbuffer[demo,setup] \page

\startbuffer[setup]
\setuplinenumbering[align=right]
\stopbuffer
\getbuffer[demo,setup] \page

\startbuffer[setup]
\setuplinenumbering[align=auto]
\stopbuffer
\getbuffer[demo,setup] \page

\stoptext
