title: What's wrong when running commandline perl here?
body: <pre><code>[root@dev-test test]$ perl -e "%hash=(key,1);print 1 if exists $hash{key};"
  exists argument is not a HASH or ARRAY element at -e line 1.
  </code></pre>
  
  <p>The above works if I put it in a file,but why command line fails?</p>