vawk '{print I$dbNSFP_GERP++_RS}' input vcf prints only 0 example line from vcf to test: 11 47353646 . C T . . dbNSFP_GERP++_RS=4.33;dbNSFP_GERP++_RS_rankscore=0.52;dbNSFP_phyloP46way_primate=-0.41;