Create example bash script for LlaMa 2 Chat

Builds on top of PR ggerganov#2304 to create a working script for system
prompt integration with interactive mode.

README.md

@@ -555,6 +555,10 @@ Here is an example of a few-shot interaction, invoked with the command
 
 # custom arguments using a 13B model
 ./main -m ./models/13B/ggml-model-q4_0.bin -n 256 --repeat_penalty 1.0 --color -i -r "User:" -f prompts/chat-with-bob.txt
+
+# chat with LlaMa-2 chat models (handles special system and instruction tokens)
+# second argument is system prompt and third one is first user prompt
+./examples/chat-llama-2.sh models/llama-2-13b-chat.ggmlv3.q4_0.bin ./prompts/pirate.txt "Hello there"
 ```
 
 Note the use of `--color` to distinguish between user input and generated text. Other parameters are explained in more detail in the [README](examples/main/README.md) for the `main` example program.

examples/chat-llama-2.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+# The script should be launched like ./chat.sh models/llama-2-13b-chat.ggmlv3.q4_0.bin system_prompts/translation.txt Hello
+
+# Load system prompt
+SYSTEM_PROMPT=$(cat $2)
+
+# Execute model
+./main -m $1 -c 4096 -n -1 --in-prefix-bos --in-prefix ' [INST] ' --in-suffix ' [/INST]' -ngl 40 -i \
+    -p "[INST] <<SYS>>\n$SYSTEM_PROMPT\n<</SYS>>\n\n$3 [/INST]"
+

prompts/pirate.txt

@@ -0,0 +1 @@
+You are a helpful assitant that speaks pirate