readme: Expand usage notes

README.md

@@ -1,8 +1,8 @@
 # yajsv
 
-Yet Another [JSON-Schema](https://json-schema.org) Validator. Command line tool for validating JSON documents against provided schemas. Assumes referenced schemas and documents are on the local file-system.
+Yet Another [JSON-Schema](https://json-schema.org) Validator. Command line tool for validating JSON documents against provided schemas.
 
-The real credit goes to [xeipuuv/gojsonschema](https://github.com/xeipuuv/gojsonschema) which this wraps to create the CLI.
+The real credit goes to [xeipuuv/gojsonschema](https://github.com/xeipuuv/gojsonschema) which does the heavy lifting behind this CLI.
 
 ## Installation
 
@@ -14,11 +14,39 @@ go get github.com/neilpa/yajsv
 
 ## Usage
 
+yajsv validates JSON documents against a schema, providing a status per document:
+
+  * pass: Document is valid relative to the schema
+  * fail: Document is invalid relative to the schema
+  * error: Document is malformed, e.g. not valid JSON
+
+The 'fail' status may be reported multiple times per-document, once for each schema validation failure.
+
+Basic usage
+
 ```
-yajsv -s schema.json [-r ref-schema.json -r ...] document.json [...]
+$ yajsv -s schema.json document.json
+document.json: pass
+```
+
+With multiple schema files and docs
 
-  -r value
-    	referenced schema(s), can be globs and/or used multiple times
-  -s string
-    	primary JSON schema to validate against
 ```
+$ yajsv -s schema.json -r foo.json -r bar.json doc1.json doc2.json
+doc1.json: pass
+doc2.json: pass
+```
+
+Or with file globs (note the quotes to side-step shell expansion)
+
+```
+$ yajsv -s main.schema.json -r '*.schema.json' 'docs/*.json'
+docs/a.json: pass
+docs/b.json: fail: Validation failure message
+...
+```
+
+Note that each of the referenced schema is assumed to be a path on the local filesystem. These are not
+URI references to either local or external schemas and documents.
+
+See `yajsv -h` for more details