And here's a complement to get rid of the gap between startStaff and stopStaff :
\version "2.18.2"
{ g d c d c d \once\hide Staff.BarLine \bar "|" \stopStaff \startStaff \override Staff.LedgerLineSpanner.length-fraction = #0.1
\override Staff.LedgerLineSpanner.minimum-length-fraction = #0.1 g d c d c d c d \once\hide Staff.BarLine \bar "|" \stopStaff \startStaff \override Staff.LedgerLineSpanner.length-fraction = #1
\override Staff.LedgerLineSpanner.minimum-length-fraction = #1 g d c d c d }