Automation is great because it saves you time. It also permits you to push work to other, less-technical people.
There are four types of problems that SAs typically deal with:
Simple things done once
Hard things done once
Simple things done often
Hard things done often
"Hard things done once" and "Simple things done often" are the right things to try to automate. "Hard things done often," while tempting, is usually better served by off-the-shelf packages (commercial or free).
To automate a process, first be sure you can do the steps manually. Then document each step, and make sure that you can automate each step. Then bring all of the steps together.
You can save a lot of typing time by making aliases. This is true for command-line systems as well as for applications, such as SSH. Set the alias as close to the actual application as possible. For example, setting the alias in the SSH configuration file means all systems that leverage SSH will use the alias.
The Unix/Linux make command is extremely powerful. It is not just for programmers. You can use it to automate system administration tasks. On Unix/Linux systems, especially servers, standardize on having a Makefile in /etc that automates common tasks such as reindexing aliases, cloning data, and so on.
Bash and /bin/sh shell languages are more sophisticated and powerful than you may realize. The examples in this chapter reveal how to parse command-line options and even how to write a small malware detector!
When writing a long command line, test each part as you write it.
When writing code for other people, the user interface becomes more important. There are tricks and techniques to creating useful user interfaces. You can avoid the issue by shifting all data entry to a program like MS Excel or by providing a menu system or web interface that lets people access higher-privileged systems.
When writing code to let users do privileged operations, be extremely careful. Build on security tools that already exist and have good credibility, such as sudo. Use a permission table to explain to management who will have access to what. It is their job to manage risk and your job to help them understand the issues. Get approval before you deploy the system.
As you move through your career, you will find yourself automating more and more tasks. It is a good idea to learn a programming language suited for system administration functions, such as Perl, Python, Ruby, or Shell, as well as operating-specific techniques like those featured in the O'Reilly Cookbook series mentioned previously in this book.
