Printing only odd bar numbers

To print only the odd bar numbers you must set the barNumberVisibility

• to a mode showing all bar numbers
• based on a calculation of the bar numbers to be visible.

Moreover, the Score.BarNumber #'break-visibility should be overridden e.g. to #all-visible

This is best placed in a \layout block to keep the music part "clean".

The first bar number can also be printed by inserting \bar "" before the music.

This modulo function can also be used in a more general way!

\version "2.24"

%% http://lsr.di.unimi.it/LSR/Item?id=712

%LSR modified/updated by P.P.Schneider on Feb 15, 2014.

\layout { 
  \context { 
    \Score 
    barNumberVisibility = #all-bar-numbers-visible 
    % this line hereunder is just to fix a v2.18.0 bug (P.P.Schneider Feb.2014)
    % (see : http://lilypond.1069038.n5.nabble.com/Bar-number-on-odd-bars-does-not-work-on-new-release-td157263.html)
    barNumberVisibility = #(lambda (n x) (= (modulo n 2) 1)) 
    % for higher version use :
    %barNumberVisibility = #(modulo-bar-number-visible 2 1) % or 2 0 to see the even bar numbers 
    \override BarNumber.break-visibility = #all-visible 
  } 
} 

\new Staff { 
  \bar ""
  \repeat unfold 8 { c'2 c' } 
}