If Agilent provides a supported driver for your version and distribution of linux, then it is possible. I could not tell from Agilent's website. A quick google search yielded some information on a couple GPIB libraries available on sourceforge, specifically talking about the
Agilent 82357a, which may or may not be of interest to you.
For NI GPIB cards, we have a
GPIB Installation/Configuration Troubleshooter page containing a list of all the drivers for each NI GPIB device, along with the most recent driver.
Hope this helps,
Dillon M
Applications Engineer
National Instruments
TheDillo