sum: handle multiple file args
sum: handle multiple file args

polapl/coreutils,uutils/coreutils,samfoo/coreutils,dbrgn/coreutils,Gianbaoluo/coreutils,Arcterus/coreutils,silvio/rust-coreutils,Heather/coreutils,sshling/coreutils,jbcrail/coreutils,filmor/coreutils,ebfe/coreutils,kevgeniy/coreutils,jbcrail/coreutils,dokaptur/coreutils,kball/coreutils,beni55/coreutils,ebfe/coreutils,polapl/coreutils,Shir0kamii/coreutils,efuquen/coreutils,bundai223/coreutils,dennis/coreutils,efuquen/coreutils,retep998/coreutils,steveklabnik/coreutils,wimh/coreutils,Gianbaoluo/coreutils,retep998/coreutils,hexsel/coreutils,dennis/coreutils,bundai223/coreutils,mauricio/coreutils,sshling/coreutils,steveklabnik/coreutils,hexsel/coreutils,wimh/coreutils,Shtong/coreutils,mauricio/coreutils,uutils/coreutils,filmor/coreutils,Arcterus/coreutils,keunwoo/coreutils,tempbottle/coreutils,kball/coreutils,kwantam/coreutils,Shtong/coreutils,kevgeniy/coreutils,silvio/rust-coreutils,tempbottle/coreutils,dbrgn/coreutils,samfoo/coreutils,keunwoo/coreutils,Heather/coreutils,Shir0kamii/coreutils,uutils/coreutils,kwantam/coreutils,beni55/coreutils,dbrgn/coreutils