diff --git a/pkg/commands/commands.go b/pkg/commands/commands.go
index 7a491694a..ae4ffeee7 100644
--- a/pkg/commands/commands.go
+++ b/pkg/commands/commands.go
@@ -1,7 +1,6 @@
 package commands
 
 import (
-	"fmt"
 	"os"
 
 	"github.com/codegangsta/cli"
@@ -10,26 +9,8 @@ import (
 	// . "github.com/moul/advanced-ssh-config/pkg/logger"
 )
 
-var SSHFlags = []cli.Flag{}
-
 func init() {
 	config.ASSHBinary = os.Args[0]
-
-	// Populate SSHFlags
-	boolFlags := []string{"1", "2", "4", "6", "A", "a", "C", "f", "G", "g", "K", "k", "M", "N", "n", "q", "s", "T", "t", "V", "v", "X", "x", "Y", "y"}
-	stringFlags := []string{"b", "c", "D", "E", "e", "F", "I", "i", "L", "l", "m", "O", "o", "p", "Q", "R", "S", "W", "w"}
-	for _, flag := range boolFlags {
-		SSHFlags = append(SSHFlags, cli.BoolFlag{
-			Name: flag,
-		})
-	}
-	for _, flag := range stringFlags {
-		SSHFlags = append(SSHFlags, cli.StringFlag{
-			Name:  flag,
-			Value: "",
-		})
-	}
-	fmt.Println(SSHFlags)
 }
 
 // Commands is the list of cli commands
@@ -89,6 +70,6 @@ var Commands = []cli.Command{
 		Name:   "wrapper",
 		Usage:  "Initialize assh, then run SSH",
 		Action: cmdWrapper,
-		Flags:  SSHFlags,
+		Flags:  config.SSHFlags,
 	},
 }
diff --git a/pkg/commands/wrapper.go b/pkg/commands/wrapper.go
index 375a72ad4..a22be4b4b 100644
--- a/pkg/commands/wrapper.go
+++ b/pkg/commands/wrapper.go
@@ -5,17 +5,31 @@ import (
 
 	"github.com/codegangsta/cli"
 
+	"github.com/moul/advanced-ssh-config/pkg/config"
 	. "github.com/moul/advanced-ssh-config/pkg/logger"
 )
 
 func cmdWrapper(c *cli.Context) {
-	/*conf, err := config.Open()
+	if len(c.Args()) < 1 {
+		Logger.Fatalf("Missing <target> argument. See usage with 'assh wrapper -h'.")
+	}
+
+	target := c.Args()[0]
+	command := c.Args()[1:]
+	options := []string{}
+	// FIXME: populate options
+
+	Logger.Debugf("Wrapper called with target=%v command=%v ssh-options=%v", target, command, options)
+
+	conf, err := config.Open()
 	if err != nil {
 		Logger.Fatalf("Cannot open configuration file: %v", err)
-	}*/
+	}
 
-	Logger.Debugf("Wrapper called with %v", c.Args())
-	fmt.Println(c.Args())
+	fmt.Println(conf.NeedsARebuildForTarget(target))
+	//host := conf.GetHostSafe(target)
+	//fmt.Println(host)
+	//fmt.Println(host.name)
 
 	//conf.WriteSshConfigTo(os.Stdout)
 }
diff --git a/pkg/config/config.go b/pkg/config/config.go
index e2cd68ea3..ca839cd7a 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -190,6 +190,50 @@ func (c *Config) GetHostSafe(name string) *Host {
 	return host
 }
 
+// NeedsARebuildForTarget returns true if the .ssh/config file needs to be rebuild for a specific target
+func (c *Config) NeedsARebuildForTarget(target string) bool {
+	parts := strings.Split(target, "/")
+
+	// compute lists
+	aliases := map[string]bool{}
+	for _, host := range c.Hosts {
+		for _, alias := range host.Aliases {
+			aliases[alias] = true
+		}
+	}
+
+	patterns := []string{}
+	for origPattern, host := range c.Hosts {
+		patterns = append(patterns, origPattern)
+		patterns = append(patterns, host.Aliases...)
+	}
+
+	for _, part := range parts {
+		// check for direct hostname matching
+		if _, ok := c.Hosts[part]; ok {
+			continue
+		}
+
+		// check for direct alias matching
+		if _, ok := aliases[part]; ok {
+			continue
+		}
+
+		// check for pattern matching
+		for _, pattern := range patterns {
+			matched, err := path.Match(pattern, part)
+			if err != nil {
+				continue
+			}
+			if matched {
+				return true
+			}
+		}
+	}
+
+	return false
+}
+
 // LoadConfig loads the content of an io.Reader source
 func (c *Config) LoadConfig(source io.Reader) error {
 	buf, err := ioutil.ReadAll(source)