We have been able to build our skills with AWK, piece by piece, and what we have learned has been useful. We can take these tiny steps and add them to start creating something a little more usable. Perhaps we want to print just standard users; these are usually users higher than 500 or 1,000 depending on your particular distribution.
On the Linux Mint distribution that I am using for this book, standard users start with UID 1000. The UID is the third field. This is really a simple matter of using the value of the third field as the range operator. We can see this in the following example:
$ awk -F":" '$3 > 999 ' /etc/passwd
We can show users whose UID is 101 or lower with the following command:
$ awk -F":" '$3 < 101 ' /etc/passwd
These just give you an idea of some of the possibilities available with AWK. The reality is that we can play all day with our arithmetic comparison operators.
We have also seen that, with some of these examples, the awk statements become a little long. This is where we can implement the awk control files. Let's take a look at these straightaway before we get lost in a morass of syntax.