More often than not, you'll get a better result (often more safely) by writing a small thing which generates the complete command lines for all the tasks which

More often than not, you'll get a better result (often more safely) by writing a small thing which generates the complete command lines for all the tasks which need running. Then once you are happy the right thing will be done, feed the list of commands to GNU parallel or something else which does the same thing. Not only does this approach provide confidence before pulling the trigger, but the list of commands may be retained forever for reference / example. It's also clearer and doesn't get the reader mystified by "shell wizardry", as some people are wont to be.