Greet

Being a programmer can be a lonely job. Thankfully by the power of automation that is not the case! Let's create a greeter app to fend off our demons of loneliness!

Start by creating a directory named greet, and within it, add a file, greet.go with the following code in it:

package main

import (
    "fmt"
    "log"
    "os"

    "github.com/urfave/cli/v2"
)

func main() {
    app := &cli.App{
        Name:  "greet",
        Usage: "fight the loneliness!",
        Action: func(*cli.Context) error {
            fmt.Println("Hello friend!")
            return nil
        },
    }

    if err := app.Run(os.Args); err != nil {
        log.Fatal(err)
    }
}

Install our command to the $GOPATH/bin directory:

$ go install

Finally run our new command:

$ greet
Hello friend!

cli also generates neat help text:

$ greet help
NAME:
    greet - fight the loneliness!

USAGE:
    greet [global options] command [command options] [arguments...]

COMMANDS:
    help, h  Shows a list of commands or help for one command

GLOBAL OPTIONS
    --help, -h  show help (default: false)