crond is a background daemon that parses individual crontab files and executes commands on behalf of the users in question. This lightweight cron daemon aims to be simple and secure, with just enough features to stay useful. It was written from scratch by Matt Dillon in 1994. It's now developed and maintained by Jim Pryor.

In the author's opinion, having to combine a cron daemon with another daemon like anacron makes for too much complexity. So the goal is a simple cron daemon that can also take over the central functions of anacron. Unlike other fatter cron daemons, though, this cron doesn't even try to manage environment variables or act as a shell. All jobs are run with `/bin/sh` for conformity and portability. We don't try to use the user's preferred shell: that breaks down for special users and even makes some of us normal users unhappy (for example, /bin/csh does not use a true O_APPEND mode and has difficulty redirecting stdout and stderr both to different places!). You can, of course, run shell scripts in whatever language you like by making them executable with #!/bin/csh or whatever as the first line. If you don't like the extra processes, just `exec` them.