Thanks. Reza Khayat, PhD Assistant Professor City College of New York Department of Chemistry New York, NY 10031 ________________________________________ From: CCP4 bulletin board <[log in to unmask]> on behalf of Michal Jamroz <[log in to unmask]> Sent: Thursday, July 7, 2016 2:24 PM To: [log in to unmask] Subject: Re: [ccp4bb] Random selection of atoms in PDB just read you want to replace occ/bfactor, so add one pipe more: grep '^ATOM' $pdb | shuf |tail -n`echo "($percent * $N)/1"|bc` |awk '{val=substr($0,57,10);gsub(val,"0.00 0.00",$0)}1' Dnia 2016-07-07, o godz. 20:06:54 Michal Jamroz <[log in to unmask]> napisał(a): > the same with bash oneliner: > > pdb='2pcy.pdb; percent=0.1; N=`grep -c '^ATOM' $pdb`; grep '^ATOM' > $pdb| shuf |tail -n`echo "($percent * $N)/1"|bc`