mage -> just

just is more widely used thus has better tab completion, etc.
also it's easier to write a justfile than a magefile

justfile

@@ -0,0 +1,26 @@
+binary := "fml"
+build_dir := "bin"
+cmd := "./cmd/" + binary
+output := "." / build_dir / binary
+
+default: run
+
+# build binary
+build:
+	go build -o {{output}} {{cmd}}
+
+# run from source
+run:
+	go run {{cmd}}
+
+# build 'n run
+run-binary: build
+	exec {{output}}
+
+# run with args
+run-args args:
+	go run {{cmd}} {{args}}
+
+# clean up after yourself
+clean:
+	rm {{output}}

magefile.go

@@ -1,38 +0,0 @@
-//go:build mage
-
-package main
-
-import (
-	"fmt"
-	"os"
-
-	"github.com/magefile/mage/sh"
-)
-
-var (
-	binaryName string = "fml"
-	buildDir   string = "bin"
-	cmd        string = fmt.Sprintf(".%[1]ccmd%[1]c%[2]s", os.PathSeparator, binaryName)
-	output     string = fmt.Sprintf(".%[1]c%[2]s%[1]c%[3]s", os.PathSeparator, buildDir, binaryName)
-)
-
-func Build() error {
-	fmt.Println("Building...")
-	return sh.Run("go", "build", "-o", output, cmd)
-}
-
-func Run() error {
-	fmt.Println("Running...")
-	return sh.RunV("go", "run", cmd)
-}
-
-func RunBinary() error {
-	Build()
-	fmt.Println("Running binary...")
-	return sh.RunV(output)
-}
-
-func Clean() error {
-	fmt.Println("Cleaning...")
-	return os.Remove(output)
-}