A nit...these scripts won't update the file if $newcolor is a substring of a color already in the file. For example if the file has:

red-orange
bluegreen
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and you try to add one of the colors red, blue, or green, your script won't add it.

The regexp should probably be anchored and chomp used:

  chomp($color);
  $seen++ if $color =~ /^$newcolor$/;
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or eq could be used instead:

  chomp($color);
  $seen++ if $color eq $newcolor;
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