Use Beyond Compare to see (and edit!) the actual bits and bytes of your files.
Let's view two text files, one typed on Windows and the other typed on a Mac. One is larger than the other. This is because the invisible line-endings are longer on text files made by PC's. To get this view:
Session->NewSession->TextCompare. Then drag your two files in with a mouse.
Opening the two files in Text Compare, Beyond Compare displays the appropriate letters.
Here are the same two text files, represented as their hexadecimal bytes. To get this view:
Session->NewSession->HexCompare. Then drag your two files in with a mouse.
Opening the two files in Hex Compare, Beyond Compare shows the hexadecimal bytes
For on-the-fly binary checking, the bottom window on every page has a right-click binary viewer context menu:
If you are a hobbyist, or educator, don't worry, you can try all this out without paying anything at first. Beyond Compare software will run at no cost for a month (30 total days, so probably more than a month). Download Beyond Compare for Mac, Linux, and Windows at Scooter Software of Madison, Wisconsin.