Now of course we all want to be able to print a little more than just Hello World. The awk command can be used to filter content from files and if needed, very large files. We should begin by printing the complete file before filtering it. In this way, we will get a feel of the syntax of the command. Later, we will see how we can add this control information into awk files to ease the command line. Using the following command, we will print all the lines from the /etc/passwd file:

$ awk ' { print } ' /etc/passwd

This is equivalent to using the $0 variable with the print statement:

$ awk ' { print $0 }' /etc/passwd

The $0 variable refers to the complete line. If there is no argument supplied to the print command, we assume that the complete line is to be printed. If we want to print just the first field from the /etc/passwd file, we can use the $1 variable. However, we will need to specify that in this file the field separator used is a colon. The...