diff --git a/core/commands/active.go b/core/commands/active.go
index 21e4b9c32bc4..777f590664ff 100644
--- a/core/commands/active.go
+++ b/core/commands/active.go
@@ -26,7 +26,7 @@ Lists running and recently run commands.
 	},
 	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
 		ctx := env.(*oldcmds.Context)
-		return res.Emit(ctx.ReqLog.Report())
+		return cmds.EmitOnce(res, ctx.ReqLog.Report())
 	},
 	Options: []cmdkit.Option{
 		cmdkit.BoolOption("verbose", verboseOptionName, "Print extra information."),
diff --git a/core/commands/config.go b/core/commands/config.go
index 8e8c690b745b..5d39b24c8771 100644
--- a/core/commands/config.go
+++ b/core/commands/config.go
@@ -167,7 +167,7 @@ NOTE: For security reasons, this command will omit your private key. If you woul
 			return err
 		}
 
-		return res.Emit(&cfg)
+		return cmds.EmitOnce(res, &cfg)
 	},
 	Encoders: cmds.EncoderMap{
 		cmds.Text: cmds.MakeTypedEncoder(func(req *cmds.Request, w io.Writer, out *map[string]interface{}) error {
@@ -319,7 +319,7 @@ var configProfileApplyCmd = &cmds.Command{
 			return err
 		}
 
-		return res.Emit(&ConfigUpdateOutput{
+		return cmds.EmitOnce(res, &ConfigUpdateOutput{
 			OldCfg: oldCfgMap,
 			NewCfg: newCfgMap,
 		})
diff --git a/core/commands/log.go b/core/commands/log.go
index 49e24056c780..30e94922c498 100644
--- a/core/commands/log.go
+++ b/core/commands/log.go
@@ -63,7 +63,8 @@ the event log.
 
 		s := fmt.Sprintf("Changed log level of '%s' to '%s'\n", subsystem, level)
 		log.Info(s)
-		return res.Emit(&MessageOutput{s})
+
+		return cmds.EmitOnce(res, &MessageOutput{s})
 	},
 	Encoders: cmds.EncoderMap{
 		cmds.Text: cmds.MakeTypedEncoder(func(req *cmds.Request, w io.Writer, out *MessageOutput) error {
@@ -83,7 +84,7 @@ subsystems of a running daemon.
 `,
 	},
 	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
-		return res.Emit(&stringList{logging.GetSubsystems()})
+		return cmds.EmitOnce(res, &stringList{logging.GetSubsystems()})
 	},
 	Encoders: cmds.EncoderMap{
 		cmds.Text: cmds.MakeTypedEncoder(func(req *cmds.Request, w io.Writer, list *stringList) error {
diff --git a/core/commands/mount_unix.go b/core/commands/mount_unix.go
index 64c35bca050a..4dd749e2ceff 100644
--- a/core/commands/mount_unix.go
+++ b/core/commands/mount_unix.go
@@ -14,6 +14,11 @@ import (
 	cmdkit "gx/ipfs/Qmde5VP1qUkyQXKCfmEUA7bP64V2HAptbJ7phuPp7jXWwg/go-ipfs-cmdkit"
 )
 
+const (
+	mountIPFSPathOptionName = "ipfs-path"
+	mountIPNSPathOptionName = "ipns-path"
+)
+
 var MountCmd = &cmds.Command{
 	Helptext: cmdkit.HelpText{
 		Tagline: "Mounts IPFS to the filesystem (read-only).",
@@ -72,8 +77,8 @@ baz
 `,
 	},
 	Options: []cmdkit.Option{
-		cmdkit.StringOption("ipfs-path", "f", "The path where IPFS should be mounted."),
-		cmdkit.StringOption("ipns-path", "n", "The path where IPNS should be mounted."),
+		cmdkit.StringOption(mountIPFSPathOptionName, "f", "The path where IPFS should be mounted."),
+		cmdkit.StringOption(mountIPNSPathOptionName, "n", "The path where IPNS should be mounted."),
 	},
 	Run: func(req *cmds.Request, res cmds.ResponseEmitter, env cmds.Environment) error {
 		cfg, err := cmdenv.GetConfig(env)
@@ -91,13 +96,13 @@ baz
 			return err
 		}
 
-		fsdir, found := req.Options["f"].(string)
+		fsdir, found := req.Options[mountIPFSPathOptionName].(string)
 		if !found {
 			fsdir = cfg.Mounts.IPFS // use default value
 		}
 
 		// get default mount points
-		nsdir, found := req.Options["n"].(string)
+		nsdir, found := req.Options[mountIPNSPathOptionName].(string)
 		if !found {
 			nsdir = cfg.Mounts.IPNS // NB: be sure to not redeclare!
 		}
@@ -110,7 +115,7 @@ baz
 		var output config.Mounts
 		output.IPFS = fsdir
 		output.IPNS = nsdir
-		return res.Emit(&output)
+		return cmds.EmitOnce(res, &output)
 	},
 	Type: config.Mounts{},
 	Encoders: cmds.EncoderMap{
diff --git a/core/commands/sysdiag.go b/core/commands/sysdiag.go
index 55bc5a43e4bc..800bf4455ac0 100644
--- a/core/commands/sysdiag.go
+++ b/core/commands/sysdiag.go
@@ -54,7 +54,7 @@ Prints out information about your computer to aid in easier debugging.
 
 		info["ipfs_version"] = version.CurrentVersionNumber
 		info["ipfs_commit"] = version.CurrentCommit
-		return res.Emit(info)
+		return cmds.EmitOnce(res, info)
 	},
 }