perl -MIPC::Open3 -MPOSIX=WNOHANG -e "open CPYOUT,'>&STDOUT';open CPYERR,'>&STDERR';$pid=open3(\*IN,'>&CPYOUT','>&CPYERR','perl','-pe','END {warn qq(Finished\n)}');close CPYOUT;close CPYERR;print IN 'Hello',$/;close IN;sleep 3;waitpid $pid,WNOHANG"