The crontab command has one of the worst UI problems:<p>1. &quot;crontab -e&quot; lets you edit your crontab file, and &quot;crontab -r&quot; deletes it (without asking). The two keys are next to each other.<p>2. &quot;crontab&quot; (no arg) reads the contents of the crontab file from stdin and replaces it. When you accidentally hit Ctrl-D after it, your crontab is replaced with an empty file.