One of the most annoying thing when working with terraform is the size of output of the terraform plan command. For more complex environments, it easily can get to many thousand lines, even for what seems to be a small change. It makes very hard to confirm that a code change does not have a side effects.
It would be nice to have the summary option, showing only resources and modules changed. I guess one day such feature will be added. In the meantime, I thought to use the grep command on the terraform plan output. It wasn't easy, because the output contain a few control character. After quite a few attempts, I found that following regex is a substitute.
terraform plan | grep -E "^[[:cntrl:]][[:print:]]+[[:space:]]+#\ "
