# Insert lyrics verse before lineNo (in a MuseScore 2 .mscx file)
# gawk -f #InsertLine.awk < score.mcsx
# gawk -v lineNo=1 -f #InsertLine.awk < score.mcsx

BEGIN {
	lyrics = 0
	# verses are numbered 0--(n-1)
	if (--lineNo < 0) { lineNo = 0 }
	no = 0
	noString = ""
}

# <Lyrics> ----------------------------------------------------------------------------------------
/^ +<Lyrics>/ {
	lyrics = 1
	no = 0
	noString = ""
}

	/^ +<no>[0-9]+<\/no>/ {
		if (lyrics > 0) {
			noString = $0
			no = gensub(/.*<no>(.*)<\/no>/,"\\1","g",noString)
			next
		}
	}

/^ +<\/Lyrics>/ {
		if (no >= lineNo) { ++no }
		print "<no>" no "</no>" 
		lyrics = 0
}

{ print $0 }

# Output ------------------------------------------------------------------------------------------
END {}