I'm going through the instructions page on https://gatkforums.broadinstitute.org/gatk/discussion/1601/how-can-i-prepare-a-fasta-file-to-use-as-reference 

Specifically, the command I don't see how to do is:

    java -jar CreateSequenceDictionary.jar R= Homo_sapiens_assembly18.fasta O= Homo_sapiens_assembly18.dict
    [Fri Jun 19 14:09:11 EDT 2009] net.sf.picard.sam.CreateSequenceDictionary R= Homo_sapiens_assembly18.fasta O= Homo_sapiens_assembly18.dict
    [Fri Jun 19 14:09:58 EDT 2009] net.sf.picard.sam.CreateSequenceDictionary done.
    Runtime.totalMemory()=2112487424
    44.922u 2.308s 0:47.09 100.2%   0+0k 0+0io 2pf+0w

I think that `CreateSequenceDictionary.jar` comes from Picard, so I downloaded that from https://broadinstitute.github.io/picard/, but I don't see  `CreateSequenceDictionary.jar` anywhere in the directory.  However, I do see 

`CreateSequenceDictionary.java`

I assume that `.jar` files are analogous to C executables, and `.java` files are analogous to `.c` human-readable code.

Going through the Picard readme file, I see that I should execute `./gradlew shadowJar` but this build fails on two different computers that I'm on.

So I can't make/get `CreateSequenceDictionary.jar`

I'm at a loss, how do I generate this dict file?
Picard is a wrapper command that will run the subcommands. There is no single executable for each subcommand. Simply run `picard.jar` and then check the output printed to screen for the subcommand you want. Then run `java -jar picard.jar <subcommand>`