Error: Process completed with exit code 1

Question

I have been trying to automate and to update the authors.md whenever there is a new pull request and update it using the github action and below is the code for it

name: Add Contributor to AUTHORS.md
on:
  pull_request:
    types:
      - opened
      - synchronize

jobs:
  add_contributor:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout repository
        uses: actions/checkout@v3

      - name: Check if contributor already exists
        id: check_contributor
        run: |
          exists=$(grep -c -F "$GITHUB_ACTOR" AUTHORS.md)
          if [[ $exists -gt 0 ]]; then
            echo "exists=true" >> $GITHUB_ENV
          else
            echo "exists=false" >> $GITHUB_ENV
          fi
      - name: Get contributor's full name
        id: get_full_name
        if: steps.check_contributor.outputs.exists == 'false'
        run: |
          username=$GITHUB_ACTOR
          access_token=$GITHUB_TOKEN
          full_name=$(curl -s -H "Authorization: token $access_token" "https://api.github.com/users/$username" | jq -r '.name')
          if [[ -z "$full_name" ]]; then
            full_name=$username
          fi
          echo "full_name=$full_name" >> $GITHUB_ENV
      - name: Append contributor to AUTHORS.md
        id: append_contributor
        if: steps.check_contributor.outputs.exists == 'false'
        run: |
          echo "| $full_name | $GITHUB_ACTOR |" >> AUTHORS.md
      - name: Commit and push changes
        if: steps.check_contributor.outputs.exists == 'false'
        run: |
          git config --local user.email "action@github.com"
          git config --local user.name "GitHub Action"
          git add AUTHORS.md
          git commit -m "Add $GITHUB_ACTOR to AUTHORS.md"
          git push

but the github action is failing at the line exists=$(grep -c -F "$GITHUB_ACTOR" AUTHORS.md), can someone help and tell me how to resolve it

error i am getting

Run exists=$(grep -c -F "$GITHUB_ACTOR" AUTHORS.md)
Error: Process completed with exit code 1.

UPDATES:

name: Add Contributor to AUTHORS.md
on:
  pull_request:
    types:
      - opened
      - synchronize

jobs:
  add_contributor:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout repository
        uses: actions/checkout@v3

      - name: Check if contributor already exists
        id: check_contributor
        run: |
          exists=$(grep -c -F "$GITHUB_ACTOR" AUTHORS.md)
          if [[ $exists -gt 0 ]]; then
            echo "exists=true" >> $GITHUB_OUTPUT
          else
            echo "exists=false" >> $GITHUB_OUTPUT
          fi
      - name: Get contributor's full name
        id: get_full_name
        if: steps.check_contributor.outputs.exists == 'false'
        run: |
          username=$GITHUB_ACTOR
          access_token=$GITHUB_TOKEN
          full_name=$(curl -s -H "Authorization: token $access_token" "https://api.github.com/users/$username" | jq -r '.name')
          if [[ -z "$full_name" ]]; then
            full_name=$username
          fi
          echo "full_name=$full_name" >> $GITHUB_OUTPUT
      - name: Append contributor to AUTHORS.md
        id: append_contributor
        if: steps.check_contributor.outputs.exists == 'false'
        run: |
          full_name=${{ steps.get_full_name.outputs.full_name }}
          echo "| $full_name | $GITHUB_ACTOR |" >> AUTHORS.md
      - name: Commit and push changes
        if: steps.check_contributor.outputs.exists == 'false'
        run: |
          git config --local user.email "action@github.com"
          git config --local user.name "GitHub Action"
          git add AUTHORS.md
          git commit -m "Add $GITHUB_ACTOR to AUTHORS.md"
          git push

try to do some changes and also tried set+x method it is not working so removed it .

also tried to store to github outputs