Starting the Scan Package

We have the skeleton of our application ready, so let’s add the port scanning functionality, starting with the hosts list management. For this tool, we’ll create a separate package scan to develop the business logic.

Creating the hostsList.go file

Now, we create and edit the file hostsList.go. We start by defining the package name scan and the import list.

For this package, we’ll use the following packages:

• bufio to read data from files.
• errors to define error values.
• fmt to print formatted output.
• io/ioutil to write data to files.
• os for operating system-related functions.
• sort to sort the hosts list content.