Create 5x5 grid thumbnail sheet of all mp4 files in a given directory - pipe the output of this script into bash

videosheet.rb

puts "mkdir thumbs"
Dir.glob('*.mp4').sort.select{ |e| 

filename = "#{e}"
percents =  []

(4..100).step(4) do |n|
percents << n
end

for p in percents
puts "ffmpegthumbnailer -s 400 -i #{e} -t #{p}% -o thumbs/#{e}-#{p}.jpg" 
end

cmd = "montage -geometry 300x300+4+4 -tile 5x "
for p in percents
cmd << "thumbs/#{e}-#{p}.jpg "
end

cmd << " thumbs/sheet-#{e}.jpg"

puts cmd

for p in percents
	puts "rm thumbs/#{e}-#{p}.jpg"
end

}