Changing Lines per page? $=

I know it is possible to change the number of lines per 
page using $=.  Can this be changed using a variable 
such as $=$page_length and if so where do you place this 
in your code?

Any help is greatly appreciated.

• Changing Lines per page? $= by gkhgkh
• RE: Changing Lines per page? $= by Nikola Janceski