fish-shell/share/functions/up-or-search.fish

function up-or-search -d "Depending on cursor position and current mode, either search backward or move up one line"
	# If we are already in search mode, continue
	if commandline --search-mode
		commandline -f history-search-backward
		return
	end

	# We are not already in search mode.
	# If we are on the top line, start search mode, 
	# otherwise move up
	set lineno (commandline -L)

	switch $lineno
		case 1
		commandline -f history-search-backward
		
		case '*'
		commandline -f up-line
	end
end