diff --git a/api/types/types.go b/api/types/types.go
index 88e34223ea..57882b84e5 100644
--- a/api/types/types.go
+++ b/api/types/types.go
@@ -542,13 +542,13 @@ type DiskUsage struct {
 }
 
 // ImagesPruneConfig contains the configuration for Remote API:
-// POST "/image/prune"
+// POST "/images/prune"
 type ImagesPruneConfig struct {
 	DanglingOnly bool
 }
 
 // ContainersPruneConfig contains the configuration for Remote API:
-// POST "/image/prune"
+// POST "/images/prune"
 type ContainersPruneConfig struct {
 }
 
@@ -572,7 +572,7 @@ type VolumesPruneReport struct {
 }
 
 // ImagesPruneReport contains the response for Remote API:
-// POST "/image/prune"
+// POST "/images/prune"
 type ImagesPruneReport struct {
 	ImagesDeleted  []ImageDelete
 	SpaceReclaimed uint64
diff --git a/cli/command/container/prune.go b/cli/command/container/prune.go
index 7088038614..be67fe4ca9 100644
--- a/cli/command/container/prune.go
+++ b/cli/command/container/prune.go
@@ -67,7 +67,7 @@ func runPrune(dockerCli *command.DockerCli, opts pruneOptions) (spaceReclaimed u
 	return
 }
 
-// RunPrune call the Container Prune API
+// RunPrune calls the Container Prune API
 // This returns the amount of space reclaimed and a detailed output string
 func RunPrune(dockerCli *command.DockerCli) (uint64, string, error) {
 	return runPrune(dockerCli, pruneOptions{force: true})
diff --git a/cli/command/image/prune.go b/cli/command/image/prune.go
index e5ad573130..46bd56cb10 100644
--- a/cli/command/image/prune.go
+++ b/cli/command/image/prune.go
@@ -83,7 +83,7 @@ func runPrune(dockerCli *command.DockerCli, opts pruneOptions) (spaceReclaimed u
 	return
 }
 
-// RunPrune call the Image Prune API
+// RunPrune calls the Image Prune API
 // This returns the amount of space reclaimed and a detailed output string
 func RunPrune(dockerCli *command.DockerCli, all bool) (uint64, string, error) {
 	return runPrune(dockerCli, pruneOptions{force: true, all: all})
diff --git a/cli/command/prune/prune.go b/cli/command/prune/prune.go
index 0b1374eda9..fd04c590b6 100644
--- a/cli/command/prune/prune.go
+++ b/cli/command/prune/prune.go
@@ -8,32 +8,32 @@ import (
 	"github.com/spf13/cobra"
 )
 
-// NewContainerPruneCommand return a cobra prune command for containers
+// NewContainerPruneCommand returns a cobra prune command for containers
 func NewContainerPruneCommand(dockerCli *command.DockerCli) *cobra.Command {
 	return container.NewPruneCommand(dockerCli)
 }
 
-// NewVolumePruneCommand return a cobra prune command for volumes
+// NewVolumePruneCommand returns a cobra prune command for volumes
 func NewVolumePruneCommand(dockerCli *command.DockerCli) *cobra.Command {
 	return volume.NewPruneCommand(dockerCli)
 }
 
-// NewImagePruneCommand return a cobra prune command for images
+// NewImagePruneCommand returns a cobra prune command for images
 func NewImagePruneCommand(dockerCli *command.DockerCli) *cobra.Command {
 	return image.NewPruneCommand(dockerCli)
 }
 
-// RunContainerPrune execute a prune command for containers
+// RunContainerPrune executes a prune command for containers
 func RunContainerPrune(dockerCli *command.DockerCli) (uint64, string, error) {
 	return container.RunPrune(dockerCli)
 }
 
-// RunVolumePrune execute a prune command for volumes
+// RunVolumePrune executes a prune command for volumes
 func RunVolumePrune(dockerCli *command.DockerCli) (uint64, string, error) {
 	return volume.RunPrune(dockerCli)
 }
 
-// RunImagePrune execute a prune command for images
+// RunImagePrune executes a prune command for images
 func RunImagePrune(dockerCli *command.DockerCli, all bool) (uint64, string, error) {
 	return image.RunPrune(dockerCli, all)
 }
diff --git a/cli/command/system/df.go b/cli/command/system/df.go
index 085d680fe8..293946c188 100644
--- a/cli/command/system/df.go
+++ b/cli/command/system/df.go
@@ -19,7 +19,7 @@ func NewDiskUsageCommand(dockerCli *command.DockerCli) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "df [OPTIONS]",
 		Short: "Show docker disk usage",
-		Args:  cli.RequiresMaxArgs(1),
+		Args:  cli.NoArgs,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return runDiskUsage(dockerCli, opts)
 		},
diff --git a/cli/command/system/prune.go b/cli/command/system/prune.go
index 6a36fdd890..ea8a41380f 100644
--- a/cli/command/system/prune.go
+++ b/cli/command/system/prune.go
@@ -15,13 +15,13 @@ type pruneOptions struct {
 	all   bool
 }
 
-// NewPruneCommand creates a new cobra.Command for `docker du`
+// NewPruneCommand creates a new cobra.Command for `docker prune`
 func NewPruneCommand(dockerCli *command.DockerCli) *cobra.Command {
 	var opts pruneOptions
 
 	cmd := &cobra.Command{
 		Use:   "prune [OPTIONS]",
-		Short: "Remove unused data.",
+		Short: "Remove unused data",
 		Args:  cli.NoArgs,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return runPrune(dockerCli, opts)
diff --git a/cli/command/volume/prune.go b/cli/command/volume/prune.go
index dc2d3e25bc..a4bb0092d6 100644
--- a/cli/command/volume/prune.go
+++ b/cli/command/volume/prune.go
@@ -67,7 +67,7 @@ func runPrune(dockerCli *command.DockerCli, opts pruneOptions) (spaceReclaimed u
 	return
 }
 
-// RunPrune call the Volume Prune API
+// RunPrune calls the Volume Prune API
 // This returns the amount of space reclaimed and a detailed output string
 func RunPrune(dockerCli *command.DockerCli) (uint64, string, error) {
 	return runPrune(dockerCli, pruneOptions{force: true})
diff --git a/daemon/prune.go b/daemon/prune.go
index 3790cb8d36..cdab7df1bb 100644
--- a/daemon/prune.go
+++ b/daemon/prune.go
@@ -11,7 +11,7 @@ import (
 	"github.com/docker/docker/volume"
 )
 
-// ContainersPrune remove unused containers
+// ContainersPrune removes unused containers
 func (daemon *Daemon) ContainersPrune(config *types.ContainersPruneConfig) (*types.ContainersPruneReport, error) {
 	rep := &types.ContainersPruneReport{}
 
@@ -22,7 +22,7 @@ func (daemon *Daemon) ContainersPrune(config *types.ContainersPruneConfig) (*typ
 			// TODO: sets RmLink to true?
 			err := daemon.ContainerRm(c.ID, &types.ContainerRmConfig{})
 			if err != nil {
-				logrus.Warnf("failed to prune container %s: %v", c.ID)
+				logrus.Warnf("failed to prune container %s: %v", c.ID, err)
 				continue
 			}
 			if cSize > 0 {
@@ -35,7 +35,7 @@ func (daemon *Daemon) ContainersPrune(config *types.ContainersPruneConfig) (*typ
 	return rep, nil
 }
 
-// VolumesPrune remove unused local volumes
+// VolumesPrune removes unused local volumes
 func (daemon *Daemon) VolumesPrune(config *types.VolumesPruneConfig) (*types.VolumesPruneReport, error) {
 	rep := &types.VolumesPruneReport{}
 
@@ -65,7 +65,7 @@ func (daemon *Daemon) VolumesPrune(config *types.VolumesPruneConfig) (*types.Vol
 	return rep, err
 }
 
-// ImagesPrune remove unused images
+// ImagesPrune removes unused images
 func (daemon *Daemon) ImagesPrune(config *types.ImagesPruneConfig) (*types.ImagesPruneReport, error) {
 	rep := &types.ImagesPruneReport{}