If you followed a link to this article, chances are some well-intentioned editor of this wiki used the template,
- {{Lcmd}}
but forgot to say what command he was referring to. The syntax of references to LaTeX commands is
- {{Lcmd|<commandname>}}
So here's what you should do: go back to the article that links here and then edit that article (but not the Lcmd template itself, please) to correct the syntax of the reference to the {{Lcmd}} template. Thanks!