Add a bin command

cmd/cmd.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+
+	"strings"
+
+	"github.com/joho/godotenv"
+)
+
+func main() {
+	var showHelp bool
+	flag.BoolVar(&showHelp, "h", false, "show help")
+	var rawEnvFilenames string
+	flag.StringVar(&rawEnvFilenames, "f", "", "comma separated paths to .env files")
+
+	flag.Parse()
+
+	usage := `
+Run a process with a env setup from a .env file
+
+godotenv [-f ENV_FILE_PATHS] COMMAND_ARGS
+
+ENV_FILE_PATHS: comma separated paths to .env files
+COMMAND_ARGS: command and args you want to run
+
+example
+  godotenv -f /path/to/something/.env,/another/path/.env fortune
+`
+	// if no args or -h flag
+	// print usage and return
+	args := flag.Args()
+	if showHelp || len(args) == 0 {
+		fmt.Println(usage)
+		return
+	}
+
+	// load env
+	var envFilenames []string
+	if rawEnvFilenames != "" {
+		envFilenames = strings.Split(rawEnvFilenames, ",")
+	}
+
+	// take rest of args and "exec" them
+	cmd := args[0]
+	cmdArgs := args[1:len(args)]
+
+	err := godotenv.Exec(envFilenames, cmd, cmdArgs)
+	if err != nil {
+		log.Fatal(err)
+	}
+}

godotenv.go

@@ -19,6 +19,7 @@ import (
 	"bufio"
 	"errors"
 	"os"
+	"os/exec"
 	"strings"
 )
 
@@ -45,6 +46,10 @@ func Load(filenames ...string) (err error) {
 	return
 }
 
+/*
+  Read all env (with same file loading semantics as Load) but return values as
+  a map rather than automatically writing values into env
+*/
 func Read(filenames ...string) (envMap map[string]string, err error) {
 	filenames = filenamesOrDefault(filenames)
 	envMap = make(map[string]string)
@@ -65,6 +70,25 @@ func Read(filenames ...string) (envMap map[string]string, err error) {
 	return
 }
 
+/*
+  Loads env vars from the specified filenames (empty map falls back to default)
+  then executes the cmd specified.
+
+  Simply hooks up os.Stdin/err/out to the command and calls Run()
+
+  If you want more fine grained control over your command it's recommended
+  that you use `Load()` or `Read()` and the `os/exec` package yourself.
+*/
+func Exec(filenames []string, cmd string, cmdArgs []string) error {
+	Load(filenames...)
+
+	command := exec.Command(cmd, cmdArgs...)
+	command.Stdin = os.Stdin
+	command.Stdout = os.Stdout
+	command.Stderr = os.Stderr
+	return command.Run()
+}
+
 func filenamesOrDefault(filenames []string) []string {
 	if len(filenames) == 0 {
 		return []string{".env"}