test2.sh

 #!/bin/bash
 echo hello; echo there
  filename=ttt.sh
   if [ -r "$filename" ]; then    # 注意: "if"和"then"需要分隔
        echo "File $filename exists."; cp $filename $filename.bak
	 else
	      echo "File $filename not found."; touch $filename
	       fi; echo "File test complete."