diff --git a/commands/command_registry.go b/commands/command_registry.go
index 6cb6c27..a999b83 100644
--- a/commands/command_registry.go
+++ b/commands/command_registry.go
@@ -35,7 +35,7 @@ func init() {
 
 type CckCommand interface {
 	fill(context *context.Context, service string, env string)
-	execute()
+	execute() error
 }
 
 func fill(cck CckCommand, config *utils.Config, service string, env string) error {
@@ -69,6 +69,6 @@ func fill(cck CckCommand, config *utils.Config, service string, env string) erro
 	return nil
 }
 
-func execute(cck CckCommand) {
-	cck.execute()
+func execute(cck CckCommand) error {
+	return cck.execute()
 }
diff --git a/commands/contact_key.go b/commands/contact_key.go
index d49b079..04f948e 100644
--- a/commands/contact_key.go
+++ b/commands/contact_key.go
@@ -14,13 +14,11 @@ func Execute() {
 	cfg, err := utils.LoadConfig()
 	if err != nil {
 		log.Fatalln(fmt.Sprintf("Failed load config: %q", err))
-		return
 	}
 
 	services, err := cfg.DiscoverServices()
 	if err != nil {
 		log.Fatalln(fmt.Sprintf("Failed to find services: %q", err))
-		return
 	}
 
 	rootCmd := &cobra.Command{
diff --git a/commands/deploy.go b/commands/deploy.go
index 5c888d7..549adc7 100644
--- a/commands/deploy.go
+++ b/commands/deploy.go
@@ -1,6 +1,7 @@
 package commands
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -40,7 +41,7 @@ type Deploy struct {
 	Writer  io.Writer
 }
 
-func (d *Deploy) execute() {
+func (d *Deploy) execute() error {
 	timer := prometheus.NewTimer(prometheus.ObserverFunc(
 		deployDuration.With(prometheus.Labels{"env": d.Env, "project": d.Service}).Set))
 	d.Context.Metrics.Add(deployDuration)
@@ -62,8 +63,7 @@ func (d *Deploy) execute() {
 	}
 
 	if err := utils.CheckIfIsLaunchedInAScreen(); err != nil && d.Context.ScreenMandatory == true {
-		log.Errorln(fmt.Sprintf("Screen error raised: %q", err))
-		return
+		return errors.New(fmt.Sprintf("Screen error raised: %q", err))
 	}
 
 	// The lock system is not mandatory
@@ -71,17 +71,15 @@ func (d *Deploy) execute() {
 		log.Println(fmt.Sprintf("Trying to lock the lock command for service %q and env %q", d.Service, d.Env))
 		canLock, err := d.Context.LockSystem.Lock(d.Env, d.Service)
 		if err != nil {
-			log.Fatalln(fmt.Sprintf("Failed to lock, error raised: %q", err))
-			return
+			return errors.New(fmt.Sprintf("Failed to lock, error raised: %q", err))
 		}
 
 		if canLock == false {
-			log.Fatalln("Another command is currently running")
-			return
+			return errors.New("Another command is currently running")
 		}
 
 		defer func(d *Deploy) {
-			d.Context.LockSystem.Unlock(d.Env, d.Service)
+			err = d.Context.LockSystem.Unlock(d.Env, d.Service)
 			if err != nil {
 				log.Errorln(fmt.Sprintf("Failed to unlock, error raised: %q", err))
 			}
@@ -91,26 +89,22 @@ func (d *Deploy) execute() {
 	// If the branch is null it will use the default one.
 	sha1ToDeploy, err := d.Context.Vcs.RetrieveSha1ForProject(branch)
 	if err != nil {
-		log.Fatalln(fmt.Sprintf("Failed to retrieve source changes for %q : %q", d.Service, err))
-		return
+		return errors.New(fmt.Sprintf("Failed to retrieve source changes for %q : %q", d.Service, err))
 	}
 
 	podVersion, err := d.Context.Binaries.RetrievePodVersion(sha1ToDeploy)
 	if err != nil {
-		log.Fatalln(fmt.Sprintf("Failed to retrieve pod version: %q", err))
-		return
+		return errors.New(fmt.Sprintf("Failed to retrieve pod version: %q", err))
 	}
 
 	deployedVersions, err := d.Context.Deployer.ListVcsVersions(d.Env)
 	if err != nil {
-		log.Fatalln(fmt.Sprintf("Failed to retrieve DEPLOYED version from service(%q) in env %q: %q", d.Service, d.Env, err))
-		return
+		return errors.New(fmt.Sprintf("Failed to retrieve DEPLOYED version from service(%q) in env %q: %q", d.Service, d.Env, err))
 	}
 
 	if podVersion == "" {
-		log.Fatalln(fmt.Sprintf("We have not found the pod version with the the sha1 %q \n"+
+		return errors.New(fmt.Sprintf("We have not found the pod version with the the sha1 %q \n"+
 			"The pod has not been created.", sha1ToDeploy))
-		return
 	}
 
 	needToDeploy := force
@@ -125,16 +119,14 @@ func (d *Deploy) execute() {
 	}
 
 	if needToDeploy == false {
-		log.Fatalln(fmt.Sprintf("Version %q is already deployed.", sha1ToDeploy))
-		return
+		return errors.New(fmt.Sprintf("Version %q is already deployed.", sha1ToDeploy))
 	}
 
 	log.Println(fmt.Sprintf("Going to deploy pod version %q \n", podVersion))
 	for _, hook := range d.Context.Hooks {
 		err = hook.PreDeployment(userName, d.Env, d.Service, podVersion)
 		if hook.StopOnError() == true && err != nil {
-			log.Fatalln(fmt.Sprintf("Predeployment failed: %q", err))
-			return
+			return errors.New(fmt.Sprintf("Predeployment failed: %q", err))
 		} else if err != nil {
 			log.Debugln(fmt.Sprintf("Predeployment failed: %q", err))
 		}
@@ -150,8 +142,7 @@ func (d *Deploy) execute() {
 	}()
 	err = d.Context.Deployer.Deploy(d.Env, podVersion, stateStream)
 	if err != nil {
-		log.Fatalf("Deployment failed: %q", err)
-		return
+		return errors.New(fmt.Sprintf("Deployment failed: %q", err))
 	}
 
 	for _, hook := range d.Context.Hooks {
@@ -168,6 +159,7 @@ func (d *Deploy) execute() {
 	}
 
 	log.Println(d.Writer, "Deployment has successfully ended")
+	return nil
 }
 
 func (d *Deploy) fill(context *context.Context, service string, env string) {
diff --git a/commands/diff.go b/commands/diff.go
index 670cbb8..2c6ddaf 100644
--- a/commands/diff.go
+++ b/commands/diff.go
@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"os"
 
+	"errors"
+
 	"github.com/olekukonko/tablewriter"
 	"github.com/remyLemeunier/contactkey/context"
 	log "github.com/sirupsen/logrus"
@@ -26,27 +28,23 @@ type Diff struct {
 	TableWriter *tablewriter.Table
 }
 
-func (d Diff) execute() {
+func (d Diff) execute() error {
 	// If the branch is null it will use the default one.
 	sha1, err := d.Context.Vcs.RetrieveSha1ForProject(branch)
 	if err != nil {
-		log.Fatal(fmt.Sprintf("Failed to retrieve sha1: %q \n", err))
-		return
+		return errors.New(fmt.Sprintf("Failed to retrieve sha1: %q \n", err))
 	}
 	if sha1 == "" {
-		log.Fatal(fmt.Sprintf("No sha1 found for service %q \n", d.Service))
-		return
+		return errors.New(fmt.Sprintf("No sha1 found for service %q \n", d.Service))
 	}
 
 	versions, err := d.Context.Deployer.ListVcsVersions(d.Env)
 	if err != nil {
-		log.Fatal(fmt.Sprintf("Failed to list versions with error %q \n", err))
-		return
+		return errors.New(fmt.Sprintf("Failed to list versions with error %q \n", err))
 	}
 
 	if len(versions) == 0 {
-		log.Fatal(fmt.Sprintf("No service (%q) versions found for the Env: %q \n", d.Service, d.Env))
-		return
+		return errors.New(fmt.Sprintf("No service (%q) versions found for the Env: %q \n", d.Service, d.Env))
 	}
 
 	// Retrieve only unique versions
@@ -62,8 +60,7 @@ func (d Diff) execute() {
 	for _, uniqueVersion := range uniqueVersions {
 		changes, err := d.Context.Vcs.Diff(uniqueVersion, sha1)
 		if err != nil {
-			log.Fatal(fmt.Sprintf("Failed to retrieve sha1: %q \n", err))
-			return
+			return errors.New(fmt.Sprintf("Failed to retrieve sha1: %q \n", err))
 		}
 
 		log.Println(fmt.Sprintf("Diff between %q(deployed) and %q(branch) \n", uniqueVersion, sha1))
@@ -73,6 +70,7 @@ func (d Diff) execute() {
 		}
 		d.TableWriter.Render()
 	}
+	return nil
 }
 
 func (d *Diff) fill(context *context.Context, service string, env string) {
diff --git a/commands/env_service.go b/commands/env_service.go
index 775c780..98fed18 100644
--- a/commands/env_service.go
+++ b/commands/env_service.go
@@ -30,9 +30,8 @@ func addServiceNameToCommand(cmd *cobra.Command, cfg *utils.Config, services []s
 				if err != nil {
 					return err
 				}
-				execute(cckCommand)
 
-				return nil
+				return execute(cckCommand)
 			},
 		}
 		cmd.AddCommand(serviceCmd)
diff --git a/commands/list.go b/commands/list.go
index 2bb2b4b..4f834a7 100644
--- a/commands/list.go
+++ b/commands/list.go
@@ -1,13 +1,13 @@
 package commands
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"os"
 
 	"github.com/olekukonko/tablewriter"
 	"github.com/remyLemeunier/contactkey/context"
-	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 )
 
@@ -24,11 +24,10 @@ type List struct {
 	Writer      io.Writer
 }
 
-func (l List) execute() {
+func (l List) execute() error {
 	instances, err := l.Context.Deployer.ListInstances(l.Env)
 	if err != nil {
-		log.Fatalln(fmt.Sprintf("Failed to list versions : %q", err))
-		return
+		return errors.New(fmt.Sprintf("Failed to list versions : %q", err))
 	}
 
 	l.TableWriter.SetHeader([]string{"instance", "state", "version"})
@@ -36,7 +35,7 @@ func (l List) execute() {
 		l.TableWriter.Append([]string{instance.Name, instance.State, instance.Version})
 	}
 	l.TableWriter.Render()
-
+	return nil
 }
 
 func (l *List) fill(context *context.Context, service string, env string) {
diff --git a/commands/rollback.go b/commands/rollback.go
index d926dfa..f9337d4 100644
--- a/commands/rollback.go
+++ b/commands/rollback.go
@@ -16,7 +16,8 @@ type Rollback struct {
 	Context *context.Context
 }
 
-func (r *Rollback) execute() {
+func (r *Rollback) execute() error {
+	return nil
 }
 
 func (r *Rollback) fill(context *context.Context, service string, env string) {