How to launch pdf viewer from the terminal
Solution 1:
You can just use open <filename.pdf> and your OS will use the default program to view PDFs. With open -a Preview.app <filename.pdf> your PDF is opened using Preview, even if your default PDF reader is something different.
Solution 2:
After discovering the "open" answer I wrote the following shell script, which I placed in /usr/bin/acroread:
#!/bin/sh
/usr/bin/open $1
Don't forget to chmod +x /usr/bin/acroread. My LaTeX workflow is homogenized by this solution.