The readme says to navigate to src/cfml/cli (to run box shell.cfm) but that folder does not exist - and there is no shell.cfm file anywhere in the source tree.
Ooops, more documentation that hasn't kept up with our rampant refactoring. shell was renamed to /cfml/system/bootstrap.cfm. Since the shell is the default behavior now, that line in the readme is essentially moot. We'll go back through and figure out what parts of the readme still actually apply before we get our first alpha out.
For the most part, just run the binary for your OS and a .CommandBox dir will get unpacked into your user's home dir. You can play around with the code in the CFML directory and then use the reload command. Otherwise, changing the code in the repo and then running the build scripts will re-package the executable jar, cfml, code, and OS-specific binaries. There will be many changes coming soon to simplify the build process and also get things moved over to our integration server.
updated the readme.txt to reflect the path change