title: An unexpected rm occur after make
body: <p>This is the main part of my makefile:</p>
  
  <pre class="lang-python prettyprint-override"><code>#openmp
  ifeq($(BLITTZ_CC), icc)
      OPENMP_OPTIONS := -fopenmp
  else
      OPENMP_OPTIONS := -fopenmp
  endif
  
  #compiler options
  CXXFLAGS := -WALL -Wno-unused-parameter $(OPTIMIZE_OPTIONS) $(OPENMP_OPTIONS) $(MODE)
  
  SRC_LIST := $(wildcard $(SRC_DIR)/*.cpp)
  OBJ_LIST := $(patsubst %.cpp, $(BUILD_DIR)/%.o, $(notdir $(SRC_LIST)))
  TARGET := main
  BIN_TARGET := $(BIN_DIR)/$(TARGET)
  
  $(BIN_TARGET): $(OBJ_LIST)
      $(BLITZ_CC) -o $@ $(OBJ_LIST) $(CXXFLAGS)
  
  $(BUILD_DIR)/%.o: $(BUILD_DIR)/%.s
      $(BLITZ_CC) -o $@ -c $&lt; $(CXXFLAGS)
  
  $(BUILD_DIR)/%.s: $(SRC_DIR)/%.cpp
      $(BLITZ_CC) -o $@ -S $(CXXFLAGS) $&lt;
  
  #inc test
  test:
      echo $(SRC_LIST)
      echo $(OBJ_LIST)
      echo $(BIN_TARGET)
  
  #clean
  clean:
      find $(BUILD_DIR) -name *.o -exec rm rf {} \;
      find $(BUILD_DIR) -name *.s -exec rm rf {} \;
      rm $(BIN_DIR)/*
  </code></pre>
  
  <p>This is what happens after <code>make</code>:</p>
  
  <p><img src="https://i.stack.imgur.com/UWYoI.jpg" alt="enter image description here"></p>
  
  <p>Why does <code>rm *.s</code> occur here? I need the assemble files and I do not want to delete them.</p>