refactor: streamline output handling for GITHUB_OUTPUT in workflows (#404)

* refactor: streamline output handling for GITHUB_OUTPUT in workflows

- Write the stdout<<EOF and EOF markers directly to GITHUB_OUTPUT instead of using a group command
- Simplify the process for capturing and appending command output to GITHUB_OUTPUT

fix #403
fix #397

Signed-off-by: appleboy <appleboy.tw@gmail.com>

* test: enhance stdout capture and verification in tests

- Add a check to ensure captured stdout is not empty
- Add steps to capture and verify multiline stdout output
- Add verification that specific lines and the username are present in captured output
- Add steps to handle and verify stdout containing special characters and file paths

Signed-off-by: appleboy <appleboy.tw@gmail.com>

* ci: enforce unique occurrence of lines in multiline output validation

- Add a step to verify that lines "Line 1", "Line 2", and "Line 3" each appear exactly once in the multiline output
- Fail the workflow if any line is missing or duplicated
- Confirm successful validation with a message when no duplicates are found

Signed-off-by: appleboy <appleboy.tw@gmail.com>

---------

Signed-off-by: appleboy <appleboy.tw@gmail.com>

.github/workflows/main.yml

@@ -609,6 +609,102 @@ jobs:
       - name: check stdout
         run: |
           echo "stdout: ${{ steps.stdout.outputs.stdout }}"
+          if [ -z "${{ steps.stdout.outputs.stdout }}" ]; then
+            echo "Error: stdout is empty"
+            exit 1
+          fi
+
+      - id: stdout-multiline
+        name: capture multiline output
+        uses: ./
+        with:
+          host: ${{ env.REMOTE_HOST }}
+          username: linuxserver.io
+          password: password
+          port: 2222
+          capture_stdout: true
+          script: |
+            #!/usr/bin/env bash
+            set -e
+            echo "Line 1"
+            echo "Line 2"
+            echo "Line 3"
+            whoami
+            pwd
+
+      - name: check multiline output
+        run: |
+          echo "stdout: ${{ steps.stdout-multiline.outputs.stdout }}"
+          # Check if all lines are present
+          if ! echo "${{ steps.stdout-multiline.outputs.stdout }}" | grep -q "Line 1"; then
+            echo "Error: 'Line 1' not found in output"
+            exit 1
+          fi
+          if ! echo "${{ steps.stdout-multiline.outputs.stdout }}" | grep -q "Line 2"; then
+            echo "Error: 'Line 2' not found in output"
+            exit 1
+          fi
+          if ! echo "${{ steps.stdout-multiline.outputs.stdout }}" | grep -q "Line 3"; then
+            echo "Error: 'Line 3' not found in output"
+            exit 1
+          fi
+          if ! echo "${{ steps.stdout-multiline.outputs.stdout }}" | grep -q "linuxserver.io"; then
+            echo "Error: username not found in output"
+            exit 1
+          fi
+
+          # Check for duplicates - each unique line should appear exactly once
+          OUTPUT="${{ steps.stdout-multiline.outputs.stdout }}"
+          LINE1_COUNT=$(echo "$OUTPUT" | grep -c "^Line 1$" || true)
+          LINE2_COUNT=$(echo "$OUTPUT" | grep -c "^Line 2$" || true)
+          LINE3_COUNT=$(echo "$OUTPUT" | grep -c "^Line 3$" || true)
+
+          echo "Line 1 count: $LINE1_COUNT"
+          echo "Line 2 count: $LINE2_COUNT"
+          echo "Line 3 count: $LINE3_COUNT"
+
+          if [ "$LINE1_COUNT" -ne 1 ]; then
+            echo "Error: 'Line 1' appears $LINE1_COUNT times (expected 1)"
+            exit 1
+          fi
+          if [ "$LINE2_COUNT" -ne 1 ]; then
+            echo "Error: 'Line 2' appears $LINE2_COUNT times (expected 1)"
+            exit 1
+          fi
+          if [ "$LINE3_COUNT" -ne 1 ]; then
+            echo "Error: 'Line 3' appears $LINE3_COUNT times (expected 1)"
+            exit 1
+          fi
+
+          echo "✓ No duplicate lines detected"
+
+      - id: stdout-with-special-chars
+        name: capture output with special characters
+        uses: ./
+        with:
+          host: ${{ env.REMOTE_HOST }}
+          username: linuxserver.io
+          password: password
+          port: 2222
+          capture_stdout: true
+          script: |
+            #!/usr/bin/env bash
+            set -e
+            echo "Test with special chars: @#$%^&*()"
+            echo "Path: /home/user/test"
+            echo "JSON: {\"key\": \"value\"}"
+
+      - name: check special characters output
+        run: |
+          echo "stdout: ${{ steps.stdout-with-special-chars.outputs.stdout }}"
+          if ! echo "${{ steps.stdout-with-special-chars.outputs.stdout }}" | grep -q "special chars"; then
+            echo "Error: special characters test failed"
+            exit 1
+          fi
+          if ! echo "${{ steps.stdout-with-special-chars.outputs.stdout }}" | grep -q "/home/user/test"; then
+            echo "Error: path not found in output"
+            exit 1
+          fi
 
   testing-script-stop:
     runs-on: ubuntu-latest