As of version 2.4, jsonschema includes a command-line program to check some input json file against a schema specified in another file.

You can call it like so:

jsonschema -i B.json BSchema.json

Here's some example output from when I put an object where an array should be:

{u'description': u'Doubles resource collection.'}: {u'description': u'Doubles resource collection.'} is not of type u'array'

OK, since version 2.1.10 you can actually do that. Instructions are provided in the README of the project. Here is the help of the current version:

$ java -Done-jar.silent=true -jar json-schema-validator-2.1.10-standalone.jar --help
Syntax: java -jar jsonschema.jar [options] file [file...]

Options: 
    -s, --brief: only show validation status (OK/NOT OK)
    --help: show this help
    -q, --quiet: no output; exit with the relevant return code (see below)
    --syntax: check the syntax of schema(s) given as argument(s)

Exit codes:
    0: validation successful;
    1: exception occurred (appears on stderr)
    2: command line syntax error (missing argument, etc)
    100: one or more file(s) failed validation
    101: one or more schema(s) is/are invalid