Compiling multiple source files with go

Go1 the first version of go uses the '$go build' command to build programs. The best way to explain how you can compile a go program spread over multiple files is by an example.

1. Create a folder "random"

$mkdir random

2. Create a go package called "random" inside the "random" folder. We are going to use 'vim' as our editor in this example. Replace 'vim' with your favorite editor.

$vim random/random.go

3. Paste the following code in it

package random

func FirstName() string {
 return "Alice in wonderland"
}

4. Create the file for the main program

$vim names.go

5. Paste the following code in it

package main

import "fmt"
import "./random"

func main() {
 n := random.FirstName()
 fmt.Println(n)
}

- Note the 'import "./random"' statement which imports the random package which we created above.
- Note the 'package main' statement. Since this is the main file of our program we use 'package main', but in the above 'random/random.go' package we will use 'package random'
- Note how we call the 'random.FirstName()'

6. Now build the program using

$go build names.go

This will automatically compile the random package along with the main program. After running this command you will see a binary executable file called 'names' in the current directory.

$ls
names  names.go  random

7. Run the program

$./names
Alice in wonderland

Alternatively you can directly run the program using :

$go run names.go
Alice in wonderland