I added the ability for the user pick two flags to pass to the eval subroutine.

The first is the -j flag. This takes the result from the inputted hoon code , +jam's it and outputs it as a hexadecimal string.

The second is the -jk flag. This takes the result from the inputted hoon code, +jam's it and outputs the noun wrapped in the proper %khan header (leading zero, noun size, noun) as binary data.

The proper use of the eval is as follows:
echo "(add 2 2)" | urbit eval -jk > test.jam

This should be the easiest way to +jam a noun for %khan use