Display binary (not hex or od, actual ones and zeros)
 

There's no functional purpose for this, but I would very much like to display binary files as they truly are - just ones and zeros. Does anyone know of a command line program which accomplishes this task?

Well, the way the files "truly are" is one of two forms: stored charge (RAM), or magnetic fields (disk drive). So, you are going to need something like a sensitive voltmeter or magnetometer.........;)

Since demand is not high, I don't think any of the standard utilities have a binary option---thus you may need to write your own. Start with something like OD, and then set up a "case" construct to print out the binary code based on the octal output.

Well, if you were prepared to settle for the data and a GUI program to do it, you would have lots of alternatives.

xxd -b to display ones and zeroes
 

xxd -b does this.

$ cat test.txt
Test.
$ xxd -b test.txt
0000000: 01010100 01100101 01110011 01110100 00101110 00001010 Test..

Android app
 

Try Hex2bin android app if you want it for your phone.