xinitrc

[Robert Fong-tom]

I could not find the file xinitrc in order to update the .profile.  
Please tell me path for this file. I am unable to execute any of the  
macport commands. For example, the selfupdate command returns the  
error: "command could not be found". If I understabd the  
documentation, I have to modify the xinitrc file but I can't find it  
on my system. I am using a i386 Mac with OS X 10.4
Bob