if[Not]TargetInMeleeRange
As of patch 1.12 this only works on unfriendly targets for Rogue (Sinister Strike), Druid (Growl), Hunter (Wing Clip) and Warrior (Rend).
Legend
<item> is a placeholder and the entire string including <> should be replaced with the appropriate value. [text] means text is optional. {option1,option2,option3} means one of option1, option2 or option3 must be chosen. Batteries not included. UnitId can be any valid UnitId sequence as described in http://www.wowwiki.com/UnitId. Capitalization of UnitIds is not important. e.g. player, pet, target, targettarget. If the UnitId is optional, player is assumed.