Summary

In this chapter, I didn’t introduce a lot of new scripting concepts as I normally do. Instead, I showed you how to use the concepts that you already know to create scripts that might be useful to a security-conscious administrator. You’ve seen how to create shell scripts that can do simple port scans or operating system identification. Then, you saw how to create auditing scripts that can show if the root user account is enabled, when a normal user is logging into the system, and what a normal user is doing with his or her sudo privileges. After that, I showed you a script that can read a list of IP addresses, and automatically create firewall rules to block those addresses. Finally, I showed you some tips about how to find and use scripts that other people have already created.

In the next chapter, we’ll talk a bit about shell script portability. I’ll see you there.