title: Passing command-line arguments to LaTeX document
body: <p>Sometimes, I define new commands such as the following.</p>
  
  <pre><code>\newcommand{\comment}[1]{\textbf{#1}}
  %\necommand{\comment}[1]{\emph{#1}} 
  </code></pre>
  
  <p>The above commands enable me to change the style of parts of my code all at once. If I want to generate both of the possible styles, I have to compile my LaTeX document two times each time modifying the source code to enable the desired style.</p>
  
  <p>Is there a way to avoid the source code modification in such cases? That is, can I pass latex some command-line arguments so that I can choose which style to use based on that argument?</p>