ruby to make markdown links a href target blank links. sort of doesn't work with link URLs that have () in them -- like some wikipedia urls that disambiguate. also seems to convert images inadvertently as well as markdown links since they have a similar-ish format.

gistfile1.txt

File.open('test.txt', 'r+') do |f|   
    out = ""
    f.each do |line|
        out << line.gsub(/\[([^\]]+)\]\(([^)]+)\)/, '<a target="_blank" href="\2">\1</a>')
    end
    f.pos = 0                     
    f.print out
    f.truncate(f.pos)             
end