need these flags

Makefile

@@ -1,6 +1,4 @@
-all:
-	@echo
-	@echo
+all: goimports vet
 
 clean:
 	rm -f go.*
@@ -10,6 +8,9 @@ redomod:
 	GO111MODULE= go mod init
 	GO111MODULE= go mod tidy
 
+test:
+	go test
+
 vet:
 	@GO111MODULE=off go vet
 	@echo this go binary package builds okay

go.mod

@@ -1,4 +1,4 @@
-module github.com/alexflint/go-arg
+module go.wit.com/dev/alexflint/arg
 
 require (
 	github.com/alexflint/go-scalar v1.2.0

parse.go

@@ -124,8 +124,24 @@ func Parse(dest ...interface{}) error {
 	return p.Parse(flags())
 }
 
+// pass in a "pretend" os.Args. Used for bash autocomplete
+func ParseFlags(flags []string, dest ...interface{}) (*Parser, error) {
+	p, err := NewParser(Config{}, dest...)
+	if err != nil {
+		return p, err
+	}
+	overrideFlags = append(overrideFlags, flags...)
+	err = p.Parse(flags)
+	return p, err
+}
+
+var overrideFlags []string
+
 // flags gets all command line arguments other than the first (program name)
 func flags() []string {
+	if len(overrideFlags) > 0 {
+		return overrideFlags
+	}
 	if len(os.Args) == 0 { // os.Args could be empty
 		return nil
 	}