Add check for OPENAI_KEY env variable

chatgpt.sh

@@ -1,4 +1,10 @@
 #!/bin/bash
+
+if [[ -z "$OPENAI_KEY" ]]; then
+  echo "OPENAI_KEY is not set, exiting"
+  exit 1
+fi
+
 GLOBIGNORE="*"
 
 CHAT_INIT_PROMPT="You are ChatGPT, a Large Language Model trained by OpenAI. You will be answering questions from users. You answer as concisely as possible for each response (e.g. don’t be verbose). If you are generating a list, do not have too many items. Keep the number of items short. Before each user prompt you will be given the chat history in Q&A form. Output your answer directly, with no labels in front. Do not start your answers with A or Anwser. You were trained on data up until 2021. Today's date is $(date +%d/%m/%Y)"