Versioning binaries in Go

# Get version from git hash
git_hash := $(shell git rev-parse --short HEAD || echo 'development')

# Get current date
current_time = $(shell date +"%Y-%m-%d:T%H:%M:%S")

# Add linker flags
linker_flags = '-s -X main.buildTime=${current_time} -X main.version=${git_hash}'

# Build binaries for current OS and Linux
.PHONY:
build:
    @echo "Building binaries..."
    go build -ldflags=${linker_flags} -o=./bin/binver ./main.go
    GOOS=linux GOARCH=amd64 go build -ldflags=${linker_flags} -o=./bin/linux_amd64/binver ./main.go

package main

import (
    "flag"
    "fmt"
    "os"

    "github.com/morikuni/aec"
)

var (
    buildTime string
    version   string
)

const binverFigletStr = `
_     _
| |__ (_)_ ____   _____ _ __
| '_ \| | '_ \ \ / / _ \ '__|
| |_) | | | | \ V /  __/ |
|_.__/|_|_| |_|\_/ \___|_|

`

func printASCIIArt() {
    binverLogo := aec.LightGreenF.Apply(binverFigletStr)
    fmt.Println(binverLogo)
}

func main() {
    displayVersion := flag.Bool("version", false, "Display version and exit")

    flag.Parse()

    if *displayVersion {
        printASCIIArt()
        fmt.Printf("Version:\t%s\n", version)
        fmt.Printf("Build time:\t%s\n", buildTime)
        os.Exit(0)
    }
}