title: How to match exact string in perl
body: <p>I am trying to parse all the files and verify if any of the file content has strings <code>TESTDIR or TEST_DIR</code></p>
  <p>Files contents might look something like:-</p>
  <pre><code>TESTDIR = foo 
  include $(TESTDIR)/chop.mk
  ...
  TEST_DIR := goldimage
  MAKE_TESTDIR = var_make
  NEW_TEST_DIR = tesing_var
  </code></pre>
  <p>Actually I am only interested in <code>TESTDIR ,$(TESTDIR),TEST_DIR</code> but in my case last two lines should be ignored. I am new to perl , Can anyone help me out with re-rex.</p>