diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..5360807
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/autoupdate
diff --git a/example_config.yaml b/example_config.yaml
new file mode 100644
index 0000000..b819460
--- /dev/null
+++ b/example_config.yaml
@@ -0,0 +1,4 @@
+opensmtpd:
+  type: github
+  args:
+    repository: OpenSMTPD/OpenSMTPD
\ No newline at end of file
diff --git a/example_output.yaml b/example_output.yaml
new file mode 100644
index 0000000..0e98731
--- /dev/null
+++ b/example_output.yaml
@@ -0,0 +1 @@
+opensmtpd: v6.8.0p2
diff --git a/go.mod b/go.mod
index b14d51e..1e89917 100644
--- a/go.mod
+++ b/go.mod
@@ -8,7 +8,11 @@ require (
 )
 
 require (
+	github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d // indirect
 	github.com/davecgh/go-spew v1.1.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/russross/blackfriday/v2 v2.0.1 // indirect
+	github.com/shurcooL/sanitized_anchor_name v1.0.0 // indirect
+	github.com/urfave/cli v1.22.5 // indirect
 	gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c // indirect
 )
diff --git a/go.sum b/go.sum
index b0fd8d5..1cd9672 100644
--- a/go.sum
+++ b/go.sum
@@ -1,11 +1,21 @@
+github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d h1:U+s90UTSYgptZMwQh2aRr3LuazLJIa+Pg3Kc1ylSYVY=
+github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/russross/blackfriday/v2 v2.0.1 h1:lPqVAte+HuHNfhJ/0LC98ESWRz8afy9tM/0RK8m9o+Q=
+github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
+github.com/shurcooL/sanitized_anchor_name v1.0.0 h1:PdmoCO6wvbs+7yrJyMORt4/BmY5IYyJwS/kOiWx8mHo=
+github.com/shurcooL/sanitized_anchor_name v1.0.0/go.mod h1:1NzhyTcUVG4SuEtjjoZeVRXNmyL/1OwPU0+IJeTBvfc=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/urfave/cli v1.22.5 h1:lNq9sAHXK2qfdI8W+GRItjCEkI+2oR4d+MEHy1CKXoU=
+github.com/urfave/cli v1.22.5/go.mod h1:Gos4lmkARVdJ6EkW0WaNv/tZAAMe9V7XWyB60NtXRu0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
diff --git a/main.go b/main.go
index 6dd9be5..baf4dc3 100644
--- a/main.go
+++ b/main.go
@@ -1,34 +1,65 @@
 package main
 
 import (
-	"fmt"
+	"log"
+	"os"
+
+	"github.com/urfave/cli"
+	"gopkg.in/yaml.v2"
 )
 
-type Version interface {
-	String() string
-}
-
-type VersionProvider interface {
-	GetVersion() (Version, error)
-}
-
 func main() {
-	v := GitHubVersionProvider{Repository: "OpenSMTPD/OpenSMTPD"}
-	latest, err := v.GetVersion()
-	if err != nil {
-		return
-	}
-	fmt.Println(latest.String())
+	app := &cli.App{
+		Name:      "autoupdate",
+		ArgsUsage: "[CONFIG_FILE] [VERSIONS_FILE]",
 
-	yv := YamlVersionProvider{
-		File: "./versions.yml",
-		Key:  "opensmtpd_version",
-	}
+		Action: func(c *cli.Context) error {
+			if c.NArg() != 2 {
+				cli.ShowAppHelp(c)
+			}
 
-	current, err := yv.GetVersion()
-	if err != nil {
-		return
-	}
-	fmt.Println(current.String())
+			var sources map[string]struct {
+				Type string                 `yaml:"type"`
+				Args map[string]interface{} `yaml:"args"`
+			}
 
+			conf, err := os.Open(c.Args().Get(0))
+			if err != nil {
+				log.Fatal(err)
+				return err
+			}
+			defer conf.Close()
+
+			versions, err := os.Create(c.Args().Get(1))
+			if err != nil {
+				log.Fatal(err)
+				return err
+			}
+			defer versions.Close()
+
+			err = yaml.NewDecoder(conf).Decode(&sources)
+			if err != nil {
+				log.Fatal(err)
+				return err
+			}
+
+			new_versions := make(map[string]string, len(sources))
+			for name, source := range sources {
+				provider, err := GetProvider(source.Type, source.Args)
+				if err != nil {
+					log.Fatal(err)
+					return err
+				}
+				v, err := provider.GetVersion()
+				if err != nil {
+					log.Fatal(err)
+					return err
+				}
+				new_versions[name] = v.String()
+			}
+			yaml.NewEncoder(versions).Encode(new_versions)
+			return nil
+		},
+	}
+	app.Run(os.Args)
 }
diff --git a/provider.go b/provider.go
new file mode 100644
index 0000000..78f8a97
--- /dev/null
+++ b/provider.go
@@ -0,0 +1,25 @@
+package main
+
+import "fmt"
+
+type Version interface {
+	String() string
+}
+
+type VersionProvider interface {
+	GetVersion() (Version, error)
+}
+
+func GetProvider(p string, args map[string]interface{}) (VersionProvider, error) {
+	switch p {
+	case "github":
+		drafts, _ := args["drafts"].(bool)
+		prereleases, _ := args["prereleases"].(bool)
+		return &GitHubVersionProvider{
+			Repository:         args["repository"].(string),
+			IncludeDrafts:      drafts,
+			IncludePrereleases: prereleases,
+		}, nil
+	}
+	return nil, fmt.Errorf("unknown provider: %s", p)
+}