I have a list of protein GI and would like to get accession number of the genome (DBSOURCE in genbank file) using Eutilities.

What would be the easiest way to get genome accession numbers for a list of protein GI?
An alternative to perl e-util is to use the Unix e-utils. Following one liner does the job!
Note that following command would work for accession number as well as GIs as -id parameter in elink command.

    elink -db protein -id 817524604 -target nuccore|efetch -format acc