enflag is a lightweight Go library to allow environment variables overriding with command-line flags.
go get github.com/bfontaine/envflag
This example is available in example/main.go:
package main
import (
"flag"
"fmt"
"os"
"github.com/bfontaine/envflag"
)
func main() {
envflag.AutoSetup()
flag.Parse()
fmt.Printf("The key is '%s'\n", os.Getenv("KEY"))
}Once compiled, here is how to use it:
$ ./example -e KEY=42
The key is '42'
$ export KEY=43
$ ./example
The key is '43'
$ export KEY=43
$ ./example -e KEY=41
The key is '41'
$ ./example -e KEY=41 -e KEY=abcd
The key is 'abcd'