On further looking I found that C-c C-n comint-next-prompt C-c C-p comint-previous-input are both bound to the keys indicated above. They work in both iESS mode (*R* and *S* buffers) and in ess-transcript-mode (myfile.rt and myfile.st). To highlight and then remove a commandline/output region, Do C-c C-p, C-@, C-c Cn, C-w Rich