diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index c32e86f5..0eb93305 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -108,6 +108,25 @@ jobs:
           echo "${{ toJSON(steps.changed-files-specific.outputs) }}"
         shell:
           bash
+      - name: Run changed-files with specific files comma check duplicates
+        id: changed-files-specific-duplicate-output
+        uses: ./
+        with:
+          files: |
+            entrypoint.sh
+            *.sh
+      - name: Verify all_changed_files files has no duplicates
+        if: contains(steps.changed-files-specific-duplicate-output.outputs.all_modified_files, 'entrypoint.sh')
+        run: |
+          ALL_CHANGED_FILES=(${{ steps.changed-files-specific-duplicate-output.outputs.all_modified_files }})
+          UNIQUE_ALL_CHANGED_FILES=$(echo "$ALL_CHANGED_FILES" | tr ' ' '\n' | sort -u | xargs)
+
+          if [[ "$ALL_CHANGED_FILES[@]" != "$UNIQUE_ALL_CHANGED_FILES[@]" ]]; then
+            echo "Duplicate output: Expected "$UNIQUE_ALL_CHANGED_FILES" got $ALL_CHANGED_FILES"
+            exit 1
+          fi
+        shell:
+          bash
       - name: Run changed-files with specific files comma separator
         id: changed-files-specific-comma
         uses: ./
diff --git a/entrypoint.sh b/entrypoint.sh
index 1b3a56cd..4e1d6bcf 100755
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -104,25 +104,25 @@ else
   done
 
   # shellcheck disable=SC2001
-  ADDED=$(echo "${ADDED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g')
+  ADDED=$(echo "${ADDED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g' | tr ' ' '\n' | sort -u | xargs)
   # shellcheck disable=SC2001
-  COPIED=$(echo "${COPIED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g')
+  COPIED=$(echo "${COPIED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g' | tr ' ' '\n' | sort -u | xargs)
   # shellcheck disable=SC2001
-  DELETED=$(echo "${DELETED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g')
+  DELETED=$(echo "${DELETED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g' | tr ' ' '\n' | sort -u | xargs)
   # shellcheck disable=SC2001
-  MODIFIED=$(echo "${MODIFIED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g')
+  MODIFIED=$(echo "${MODIFIED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g' | tr ' ' '\n' | sort -u | xargs)
   # shellcheck disable=SC2001
-  RENAMED=$(echo "${RENAMED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g')
+  RENAMED=$(echo "${RENAMED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g' | tr ' ' '\n' | sort -u | xargs)
   # shellcheck disable=SC2001
-  TYPE_CHANGED=$(echo "${TYPE_CHANGED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g')
+  TYPE_CHANGED=$(echo "${TYPE_CHANGED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g' | tr ' ' '\n' | sort -u | xargs)
   # shellcheck disable=SC2001
-  UNMERGED=$(echo "${UNMERGED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g')
+  UNMERGED=$(echo "${UNMERGED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g' | tr ' ' '\n' | sort -u | xargs)
   # shellcheck disable=SC2001
-  UNKNOWN=$(echo "${UNKNOWN_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g')
+  UNKNOWN=$(echo "${UNKNOWN_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g' | tr ' ' '\n' | sort -u | xargs)
   # shellcheck disable=SC2001
-  ALL_CHANGED=$(echo "${ALL_CHANGED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g')
+  ALL_CHANGED=$(echo "${ALL_CHANGED_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g' | tr ' ' '\n' | sort -u | xargs)
   # shellcheck disable=SC2001
-  ALL_MODIFIED_FILES=$(echo "${ALL_MODIFIED_FILES_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g')
+  ALL_MODIFIED_FILES=$(echo "${ALL_MODIFIED_FILES_ARRAY[*]}" | sed 's/  */'"$INPUT_SEPARATOR"'/g' | tr ' ' '\n' | sort -u | xargs)
 fi
 
 echo "Added files: $ADDED"