Added file/folder I/O CLI specs (#135)

* added CLI form spec

* I/O CLI processing, force flag

* BF CLI Hackathon Flyer

* review comments

* Remove from PR

Author: Eyal

CONTRIBUTING.md

@@ -58,6 +58,7 @@
 * [--help|-h|-?] : displays help, usage information
 * [--log|-l]  [quite|normal|verbose]: Control STDOUT log level. 
   * Default: normal. Plugin owner must respect quite mode; but verbose implementation is optional
+* \[--force|-f\]: Force action without prompting e.g. Overwrite (particularly in I/O operations)
 * Short form:
   * Mandatory for common options: -i, -o, -r, -v, -h 
   * Suggested for frequent operations 
@@ -71,6 +72,36 @@
 
 - Always, if possible, detect input format from content 
 - Detect --in / --out file or folder based on specified value. If need to disambiguate introduce param (only if no way to infer).
+- Use the input/output stream tables below to guide command line I/O processing
+
+
+
+#### Input Stream
+
+| Specified | Expected | Exist  | File Action | Folder Action |
+| --------- | -------- | ------ | ----------- | ------------- |
+| Yes       | Yes      | Yes    | OK          | OK            |
+| Yes       | Yes      | No     | Fail        | Fail          |
+| No        | Yes      | Yes/No | STDIN       | Fail          |
+| Yes       | No       | Yes/No | Fail        | Fail          |
+| No        | No       | Yes/No | OK          | OK            |
+
+
+
+#### Output Stream
+
+| Specified | Expected | Exist  | File Action                                            | Folder Action                  |
+| --------- | -------- | ------ | ------------------------------------------------------ | ------------------------------ |
+| Yes       | Yes      | Yes    | if [--force] --> OK (overwrite); otherwise prompt user | Same logic for files in folder |
+| Yes       | Yes      | No     | OK (create)                                            | Fail                           |
+| No        | Yes      | Yes/No | STDOUT                                                 | Fail                           |
+| Yes       | No       | Yes/No | Fail                                                   | Fail                           |
+| No        | No       | Yes/No | OK                                                     | OK                             |
+
+
+
+
+
 
 ### Standard Command Types