Any (easy)way to copy contents of a file into X clipboard?

[Scott W]

Hey all..was wondering if anyone knew of a utlity to copy the contents 
of a text file into an X clipboard buffer?

It's possible via the use of xmessage or any other X editor that allows 
you to select all text, but something command line only would be 
useful...I'm sure something exists somewhere, but I'm not having any 
luck as of yet...anyone?

Thanks,

Scott