Add usage examples to sop-java-picocli.md

sop-java-picocli.md

@@ -1,12 +1,92 @@
 # SOP-Java-Picocli
 
-`sop-java-picocli` implements a command line interface for SOP implementations.
+`sop-java-picocli` provides a command line interface frontend for SOP implementations.
 
-## Backend Installation
+## Example Implementation
 In order to enable OpenPGP operations, you need to set an implementation of [`sop-java`](sop-java.html):
 ```java
-// static method call prior to execution of the main method
-SopCLI.setSopInstance(yourSopImpl);
+public class MySOPCLI {
+    public static void main(String[] args) {
+        // Set your own SOP backend
+        SOP mySOP = new MySOP();
+        SopCLI.setSopInstance(mySOP);
+
+        // Forward the main method
+        SopCLI.main(args);
+    }
+}
 ```
 
 ## Usage
+```bash
+$ ./sop-java-picocli help
+Usage: sop-java-picocli [COMMAND]
+Stateless OpenPGP Protocol
+Commands:
+  help                                 Displays help information about the
+                                         specified command
+  armor                                Add ASCII Armor to standard input
+  dearmor                              Remove ASCII Armor from standard input
+  decrypt                              Decrypt a message from standard input
+  detach-inband-signature-and-message  Split a clearsigned message
+  encrypt                              Encrypt a message from standard input
+  extract-cert                         Extract a public key certificate from a
+                                         secret key from standard input
+  generate-key                         Generate a secret key
+  sign                                 Create a detached signature on the data
+                                         from standard input
+  verify                               Verify a detached signature over the
+                                         data from standard input
+  version                              Display version information about the
+                                         tool
+Exit Codes:
+   0   Successful program execution
+   1   Generic program error
+   3   Verification requested but no verifiable signature found
+  13   Unsupported asymmetric algorithm
+  17   Certificate is not encryption capable
+  19   Usage error: Missing argument
+  23   Incomplete verification instructions
+  29   Unable to decrypt
+  31   Password is not human-readable
+  37   Unsupported Option
+  41   Invalid data or data of wrong type encountered
+  53   Non-text input received where text was expected
+  59   Output file already exists
+  61   Input file does not exist
+  67   Key is password protected
+  69   Unsupported subcommand
+  71   Unsupported special prefix (e.g. "@env/@fd") of indirect parameter
+  73   Ambiguous input (a filename matching the designator already exists)
+```
+
+### Generate a Key (Secret Key)
+```bash
+$ ./sop-java-picocli generage-key "Alice <alice@example.org>" > key.asc
+```
+
+### Extract a Certificate (Public Key)
+```bash
+$ ./sop-java-picocli extract-cert < key.asc > cert.asc
+```
+
+### Encrypt a Message
+```bash
+$ ./sop-java-picocli encrypt --sign-with=key.asc cert.asc < message.txt > message.asc
+```
+
+### Decrypt a Message
+```bash
+$ ./sop-java-picocli decrypt --verify-with=cert.asc --verify-out=verifications.txt key.asc < message.asc > message.txt
+$ cat verifications.txt
+```
+
+### Create a Detached Signature
+```bash
+$ ./sop-java-picocli sign key.asc < message.txt > message.txt.sig
+```
+
+### Verify a Detached Signature
+```bash
+$ ./sop-java-picocli verify message.txt.sig cert.asc < message.txt
+```