dd is a command line tool in Linux distributions. You can use dd to make bootable media easily, but one need to be careful here..
Ranked in these QuestionsQuestion Ranking
Pro Many features
It can do anything.
Pro Ported to almost any OS
There exist ports for Windows, Mac and even Android.
Con Easy to completely nuke an unrelated hard disk by accident
It is a cli app and there are no safety features to prevent a complete data loss if the user adds a wrong syntax.