diff --git a/README.md b/README.md
index 7a5243d..08769c2 100644
--- a/README.md
+++ b/README.md
@@ -151,6 +151,10 @@ Use "yutu [command] --help" for more information about a command.
 
 Please refer to [features.md](./features.md) for more information.
 
+## Contributing
+
+Please refer to [CONTRIBUTING.md](./CONTRIBUTING.md) for more information.
+
 ## Star History
 
 [![Star History Chart](https://api.star-history.com/svg?repos=eat-pray-ai/yutu&type=Date)](https://star-history.com/#eat-pray-ai/yutu&Date)
diff --git a/cmd/activity/list.go b/cmd/activity/list.go
index 1445697..c985cd1 100644
--- a/cmd/activity/list.go
+++ b/cmd/activity/list.go
@@ -31,10 +31,10 @@ func init() {
 	)
 	listCmd.Flags().BoolVarP(&home, "home", "H", true, "true or false")
 	listCmd.Flags().Int64VarP(
-		&maxResults, "maxResults", "x", 5,
+		&maxResults, "maxResults", "n", 5,
 		"Specifies the maximum number of items that should be returned",
 	)
-	listCmd.Flags().BoolVarP(&mine, "mine", "m", true, "true or false")
+	listCmd.Flags().BoolVarP(&mine, "mine", "M", true, "true or false")
 	listCmd.Flags().StringVarP(
 		&publishedAfter, "publishedAfter", "a", "",
 		"Filter on activities published after this date",
@@ -50,6 +50,6 @@ func init() {
 		"Comma separated parts",
 	)
 	listCmd.Flags().StringVarP(
-		&output, "output", "o", "", "Output format: json or yaml",
+		&output, "output", "o", "", "json or yaml",
 	)
 }
diff --git a/cmd/caption/list.go b/cmd/caption/list.go
index 0adcdaf..4bca8ae 100644
--- a/cmd/caption/list.go
+++ b/cmd/caption/list.go
@@ -25,7 +25,7 @@ func init() {
 	captionCmd.AddCommand(listCmd)
 
 	listCmd.Flags().StringVarP(&id, "id", "i", "", "ID of the caption")
-	listCmd.Flags().StringVarP(&videoId, "videoId", "I", "", "ID of the video")
+	listCmd.Flags().StringVarP(&videoId, "videoId", "v", "", "ID of the video")
 	listCmd.Flags().StringVarP(&onBehalfOf, "onBehalfOf", "b", "", "")
 	listCmd.Flags().StringVarP(&onBehalfOfContentOwner, "onBehalfOfContentOwner", "B", "", "")
 	listCmd.Flags().StringArrayVarP(&parts, "parts", "p", []string{"id", "snippet"}, "Comma separated parts")
diff --git a/cmd/channel/list.go b/cmd/channel/list.go
index 743d7fe..03ebbf1 100644
--- a/cmd/channel/list.go
+++ b/cmd/channel/list.go
@@ -31,7 +31,7 @@ func init() {
 	channelCmd.AddCommand(listCmd)
 
 	listCmd.Flags().StringVarP(
-		&categoryId, "categoryId", "c", "",
+		&categoryId, "categoryId", "g", "",
 		"Return the channels within the specified guide category ID",
 	)
 	listCmd.Flags().StringVarP(
@@ -49,7 +49,7 @@ func init() {
 		&id, "id", "i", "", "Return the channels with the specified IDs",
 	)
 	listCmd.Flags().BoolVarP(
-		&managedByMe, "managedByMe", "M", false,
+		&managedByMe, "managedByMe", "E", false,
 		"Specify the maximum number of items that should be returned",
 	)
 	listCmd.Flags().Int64VarP(
@@ -57,18 +57,18 @@ func init() {
 		"The maximum number of items that should be returned",
 	)
 	listCmd.Flags().BoolVarP(
-		&mine, "mine", "m", true,
+		&mine, "mine", "M", true,
 		"Return the ids of channels owned by the authenticated user",
 	)
 	listCmd.Flags().BoolVarP(
-		&mySubscribers, "mySubscribers", "s", false,
+		&mySubscribers, "mySubscribers", "S", false,
 		"Return the channels subscribed to the authenticated user",
 	)
 	listCmd.Flags().StringVarP(
 		&onBehalfOfContentOwner, "onBehalfOfContentOwner", "b", "", "",
 	)
 	listCmd.Flags().StringVarP(
-		&output, "output", "o", "", "Output format: json or yaml",
+		&output, "output", "o", "", "json or yaml",
 	)
 	listCmd.Flags().StringArrayVarP(
 		&parts, "parts", "p", []string{"id", "snippet", "status"},
diff --git a/cmd/channelSection/list.go b/cmd/channelSection/list.go
index a9b21b0..c6c723f 100644
--- a/cmd/channelSection/list.go
+++ b/cmd/channelSection/list.go
@@ -30,7 +30,7 @@ func init() {
 		&channelId, "channelId", "c", "", " Return the ChannelSections owned by the specified channel ID",
 	)
 	listCmd.Flags().StringVarP(&hl, "hl", "l", "", "Return content in specified language")
-	listCmd.Flags().BoolVarP(&mine, "mine", "m", false, "Return the ChannelSections owned by the authenticated user")
+	listCmd.Flags().BoolVarP(&mine, "mine", "M", false, "Return the ChannelSections owned by the authenticated user")
 	listCmd.Flags().StringVarP(&onBehalfOfContentOwner, "onBehalfOfContentOwner", "b", "", "")
 	listCmd.Flags().StringArrayVarP(&parts, "parts", "p", []string{"id", "snippet"}, "Comma separated parts")
 	listCmd.Flags().StringVarP(&output, "output", "o", "json", "json or yaml")
diff --git a/cmd/comment/insert.go b/cmd/comment/insert.go
index 5647734..35a7198 100644
--- a/cmd/comment/insert.go
+++ b/cmd/comment/insert.go
@@ -28,8 +28,8 @@ func init() {
 
 	insertCmd.Flags().StringVarP(&authorChannelId, "authorChannelId", "a", "", "Channel ID of the comment author")
 	insertCmd.Flags().StringVarP(&channelId, "channelId", "c", "", "Channel ID of the video owner")
-	insertCmd.Flags().BoolVarP(&canRate, "canRate", "r", false, "Whether the viewer can rate the comment")
-	insertCmd.Flags().StringVarP(&parentId, "parentId", "p", "", "ID of the parent comment")
+	insertCmd.Flags().BoolVarP(&canRate, "canRate", "R", false, "Whether the viewer can rate the comment")
+	insertCmd.Flags().StringVarP(&parentId, "parentId", "P", "", "ID of the parent comment")
 	insertCmd.Flags().StringVarP(&textOriginal, "textOriginal", "t", "", "Text of the comment")
 	insertCmd.Flags().StringVarP(&videoId, "videoId", "v", "", "ID of the video")
 	insertCmd.Flags().StringVarP(&output, "output", "o", "", "json, yaml or silent")
diff --git a/cmd/comment/list.go b/cmd/comment/list.go
index ba56ca6..9b0e4f1 100644
--- a/cmd/comment/list.go
+++ b/cmd/comment/list.go
@@ -26,7 +26,7 @@ func init() {
 
 	listCmd.Flags().StringSliceVarP(&ids, "ids", "i", []string{}, "Comma separated ids of comments")
 	listCmd.Flags().Int64VarP(
-		&maxResults, "maxResults", "m", 5, "Specifies the maximum number of items that should be returned",
+		&maxResults, "maxResults", "n", 5, "Specifies the maximum number of items that should be returned",
 	)
 	listCmd.Flags().StringVarP(&parentId, "parentId", "P", "", "Returns replies to the specified comment")
 	listCmd.Flags().StringVarP(&textFormat, "textFormat", "t", "", "textFormatUnspecified, html(default) or plainText")
diff --git a/cmd/comment/setModerationStatus.go b/cmd/comment/setModerationStatus.go
index 21f92db..afd9656 100644
--- a/cmd/comment/setModerationStatus.go
+++ b/cmd/comment/setModerationStatus.go
@@ -26,6 +26,6 @@ func init() {
 	setModerationStatusCmd.Flags().StringVarP(
 		&moderationStatus, "moderationStatus", "s", "", "heldForReview, published or rejected",
 	)
-	setModerationStatusCmd.Flags().BoolVarP(&banAuthor, "banAuthor", "b", false, "true or false")
+	setModerationStatusCmd.Flags().BoolVarP(&banAuthor, "banAuthor", "A", false, "true or false")
 	setModerationStatusCmd.Flags().StringVarP(&output, "output", "o", "", "json, yaml or silent")
 }
diff --git a/cmd/comment/update.go b/cmd/comment/update.go
index 513c8ae..f79ebfa 100644
--- a/cmd/comment/update.go
+++ b/cmd/comment/update.go
@@ -25,8 +25,8 @@ func init() {
 	commentCmd.AddCommand(updateCmd)
 
 	updateCmd.Flags().StringSliceVarP(&ids, "id", "i", []string{}, "ID of the comment")
-	updateCmd.Flags().BoolVarP(&canRate, "canRate", "r", false, "Whether the viewer can rate the comment")
+	updateCmd.Flags().BoolVarP(&canRate, "canRate", "R", false, "Whether the viewer can rate the comment")
 	updateCmd.Flags().StringVarP(&textOriginal, "textOriginal", "t", "", "Text of the comment")
-	updateCmd.Flags().StringVarP(&viewerRating, "viewerRating", "v", "", "none, like or dislike")
+	updateCmd.Flags().StringVarP(&viewerRating, "viewerRating", "r", "", "none, like or dislike")
 	updateCmd.Flags().StringVarP(&output, "output", "o", "", "json, yaml or silent")
 }
diff --git a/cmd/commentThread/list.go b/cmd/commentThread/list.go
index 734172b..2660abc 100644
--- a/cmd/commentThread/list.go
+++ b/cmd/commentThread/list.go
@@ -38,14 +38,15 @@ func init() {
 		&channelId, "channelId", "c", "", "Returns the comment threads for all the channel comments",
 	)
 	listCmd.Flags().Int64VarP(
-		&maxResults, "maxResults", "m", 5, "Specifies the maximum number of items that should be returned",
+		&maxResults, "maxResults", "n", 5, "Specifies the maximum number of items that should be returned",
 	)
 	listCmd.Flags().StringVarP(
-		&moderationStatus, "moderationStatus", "M", "", "published(default), heldForReview, likelySpam or rejected",
+		&moderationStatus, "moderationStatus", "m", "", "published(default), heldForReview, likelySpam or rejected",
 	)
-	listCmd.Flags().StringVarP(&order, "order", "o", "", "orderUnspecified, time(default) or relevance")
+	listCmd.Flags().StringVarP(&order, "order", "O", "", "orderUnspecified, time(default) or relevance")
 	listCmd.Flags().StringVarP(&searchTerms, "searchTerms", "s", "", "Search terms")
 	listCmd.Flags().StringVarP(&textFormat, "textFormat", "t", "", "textFormatUnspecified or html(default)")
 	listCmd.Flags().StringVarP(&videoId, "videoId", "v", "", "Returns the comment threads of the specified video")
 	listCmd.Flags().StringSliceVarP(&parts, "parts", "p", []string{"id", "snippet"}, "Parts to be fetched")
+	listCmd.Flags().StringVarP(&output, "output", "o", "", "json, yaml or silent")
 }
diff --git a/cmd/i18nLanguage/list.go b/cmd/i18nLanguage/list.go
index 4dd5210..dae04be 100644
--- a/cmd/i18nLanguage/list.go
+++ b/cmd/i18nLanguage/list.go
@@ -24,6 +24,6 @@ func init() {
 		&parts, "parts", "p", []string{"id", "snippet"}, "Comma separated parts",
 	)
 	listCmd.Flags().StringVarP(
-		&output, "output", "o", "", "Output format: json or yaml",
+		&output, "output", "o", "", "json or yaml",
 	)
 }
diff --git a/cmd/i18nRegion/list.go b/cmd/i18nRegion/list.go
index bdaf158..a2eca25 100644
--- a/cmd/i18nRegion/list.go
+++ b/cmd/i18nRegion/list.go
@@ -24,6 +24,6 @@ func init() {
 		&parts, "parts", "p", []string{"id", "snippet"}, "Comma separated parts",
 	)
 	listCmd.Flags().StringVarP(
-		&output, "output", "o", "", "Output format: json or yaml",
+		&output, "output", "o", "", "json or yaml",
 	)
 }
diff --git a/cmd/member/list.go b/cmd/member/list.go
index f80e390..d6bec03 100644
--- a/cmd/member/list.go
+++ b/cmd/member/list.go
@@ -44,6 +44,6 @@ func init() {
 		&parts, "parts", "p", []string{"snippet"}, "Comma separated parts",
 	)
 	listCmd.Flags().StringVarP(
-		&output, "output", "o", "", "Output format: json or yaml",
+		&output, "output", "o", "", "json or yaml",
 	)
 }
diff --git a/cmd/membershipsLevel/list.go b/cmd/membershipsLevel/list.go
index 8d047e5..f527023 100644
--- a/cmd/membershipsLevel/list.go
+++ b/cmd/membershipsLevel/list.go
@@ -22,6 +22,6 @@ func init() {
 		&parts, "parts", "p", []string{"id, snippet"}, "Comma separated parts",
 	)
 	listCmd.Flags().StringVarP(
-		&output, "output", "o", "", "Output format: json or yaml",
+		&output, "output", "o", "", "format: json or yaml",
 	)
 }
diff --git a/cmd/playlist/list.go b/cmd/playlist/list.go
index e432da1..0385ded 100644
--- a/cmd/playlist/list.go
+++ b/cmd/playlist/list.go
@@ -42,7 +42,7 @@ func init() {
 		&maxResults, "maxResults", "n", 5,
 		"Specifies the maximum number of items that should be returned",
 	)
-	listCmd.Flags().BoolVarP(&mine, "mine", "m", true, "Return the playlists owned by the authenticated user")
+	listCmd.Flags().BoolVarP(&mine, "mine", "M", true, "Return the playlists owned by the authenticated user")
 	listCmd.Flags().StringVarP(
 		&onBehalfOfContentOwner, "onBehalfOfContentOwner", "b", "", "",
 	)
@@ -54,6 +54,6 @@ func init() {
 		"Comma separated parts",
 	)
 	listCmd.Flags().StringVarP(
-		&output, "output", "o", "", "Output format: json or yaml",
+		&output, "output", "o", "", "json or yaml",
 	)
 }
diff --git a/cmd/playlistItem/insert.go b/cmd/playlistItem/insert.go
index fefe38f..b863425 100644
--- a/cmd/playlistItem/insert.go
+++ b/cmd/playlistItem/insert.go
@@ -46,11 +46,11 @@ func init() {
 		&kChannelId, "kChannelId", "C", "", "ID of the channel if kind is channel",
 	)
 	insertCmd.Flags().StringVarP(
-		&kPlaylistId, "kPlaylistId", "P", "",
+		&kPlaylistId, "kPlaylistId", "Y", "",
 		"ID of the playlist if kind is playlist",
 	)
 	insertCmd.Flags().StringVarP(
-		&playlistId, "playlistId", "p", "",
+		&playlistId, "playlistId", "y", "",
 		"The ID that YouTube uses to uniquely identify the playlist that the playlist item is in",
 	)
 	insertCmd.Flags().StringVarP(
@@ -58,7 +58,7 @@ func init() {
 		"The ID that YouTube uses to uniquely identify the user that added the item to the playlist",
 	)
 	insertCmd.Flags().StringVarP(
-		&privacy, "privacy", "r", "", "public, private, or unlisted",
+		&privacy, "privacy", "p", "", "public, private, or unlisted",
 	)
 	insertCmd.Flags().StringVarP(&onBehalfOfContentOwner, "onBehalfOfContentOwner", "b", "", "")
 	insertCmd.Flags().StringVarP(&output, "output", "o", "", "json, yaml or silent")
diff --git a/cmd/playlistItem/list.go b/cmd/playlistItem/list.go
index 8a7721f..bb31820 100644
--- a/cmd/playlistItem/list.go
+++ b/cmd/playlistItem/list.go
@@ -27,7 +27,7 @@ func init() {
 
 	listCmd.Flags().StringVarP(&id, "id", "i", "", "ID of the playlist item")
 	listCmd.Flags().StringVarP(
-		&playlistId, "playlistId", "I", "",
+		&playlistId, "playlistId", "y", "",
 		"Return the playlist items within the given playlist",
 	)
 	listCmd.Flags().Int64VarP(
@@ -42,7 +42,7 @@ func init() {
 		&onBehalfOfContentOwner, "onBehalfOfContentOwner", "b", "", "",
 	)
 	listCmd.Flags().StringVarP(
-		&output, "output", "o", "", "Output format: json or yaml",
+		&output, "output", "o", "", "json or yaml",
 	)
 	listCmd.Flags().StringArrayVarP(
 		&parts, "parts", "p", []string{"id", "snippet", "status"},
diff --git a/cmd/search/list.go b/cmd/search/list.go
index 2b79179..a8559fd 100644
--- a/cmd/search/list.go
+++ b/cmd/search/list.go
@@ -155,5 +155,5 @@ func init() {
 	listCmd.Flags().StringSliceVar(
 		&parts, "parts", []string{"id", "snippet"}, "Comma separated parts",
 	)
-	listCmd.Flags().StringVar(&output, "output", "", "Output format: json or yaml")
+	listCmd.Flags().StringVar(&output, "output", "", "json or yaml")
 }
diff --git a/cmd/subscription/list.go b/cmd/subscription/list.go
index a051bdc..0c42170 100644
--- a/cmd/subscription/list.go
+++ b/cmd/subscription/list.go
@@ -46,12 +46,12 @@ func init() {
 		&maxResults, "maxResults", "n", 5,
 		"Specifies the maximum number of items that should be returned",
 	)
-	listCmd.Flags().BoolVarP(&mine, "mine", "m", true, "Return the subscriptions of the authenticated user")
+	listCmd.Flags().BoolVarP(&mine, "mine", "M", true, "Return the subscriptions of the authenticated user")
 	listCmd.Flags().BoolVarP(
-		&myRecentSubscribers, "myRecentSubscribers", "r", false, "true  or false",
+		&myRecentSubscribers, "myRecentSubscribers", "R", false, "true  or false",
 	)
 	listCmd.Flags().BoolVarP(
-		&mySubscribers, "mySubscribers", "s", false, "Return the subscribers of the given channel owner",
+		&mySubscribers, "mySubscribers", "S", false, "Return the subscribers of the given channel owner",
 	)
 	listCmd.Flags().StringVarP(
 		&onBehalfOfContentOwner, "onBehalfOfContentOwner", "b", "", "",
@@ -64,7 +64,7 @@ func init() {
 		"subscriptionOrderUnspecified, relevance(default), unread or alphabetical",
 	)
 	listCmd.Flags().StringVarP(
-		&output, "output", "o", "", "Output format: json or yaml",
+		&output, "output", "o", "", "json or yaml",
 	)
 	listCmd.Flags().StringArrayVarP(
 		&parts, "parts", "p", []string{"id", "snippet"}, "Comma separated parts",
diff --git a/cmd/video/insert.go b/cmd/video/insert.go
index 3e894dd..54ec460 100644
--- a/cmd/video/insert.go
+++ b/cmd/video/insert.go
@@ -41,7 +41,7 @@ func init() {
 	videoCmd.AddCommand(insertCmd)
 
 	insertCmd.Flags().BoolVarP(
-		&autoLevels, "autoLevels", "a", true, "Should auto-levels be applied to the upload",
+		&autoLevels, "autoLevels", "A", true, "Should auto-levels be applied to the upload",
 	)
 	insertCmd.Flags().StringVarP(&file, "file", "f", "", "Path to the video file")
 	insertCmd.Flags().StringVarP(&title, "title", "t", "", "Title of the video")
@@ -49,7 +49,7 @@ func init() {
 		&description, "description", "d", "", "Description of the video",
 	)
 	insertCmd.Flags().StringArrayVarP(
-		&tags, "tags", "T", []string{}, "Comma separated tags",
+		&tags, "tags", "a", []string{}, "Comma separated tags",
 	)
 	insertCmd.Flags().StringVarP(
 		&language, "language", "l", "", "Language of the video",
@@ -74,18 +74,18 @@ func init() {
 		"Privacy status of the video: public, private, or unlisted",
 	)
 	insertCmd.Flags().BoolVarP(
-		&forKids, "forKids", "k", false, "Whether the video is for kids",
+		&forKids, "forKids", "K", false, "Whether the video is for kids",
 	)
 	insertCmd.Flags().BoolVarP(
-		&embeddable, "embeddable", "e", true, "Whether the video is embeddable",
+		&embeddable, "embeddable", "E", true, "Whether the video is embeddable",
 	)
 	insertCmd.Flags().StringVarP(
 		&publishAt, "publishAt", "U", "",
 		"Datetime when the video is scheduled to publish",
 	)
-	insertCmd.Flags().BoolVarP(&stabilize, "stabilize", "s", true, "Should stabilize be applied to the upload")
+	insertCmd.Flags().BoolVarP(&stabilize, "stabilize", "S", true, "Should stabilize be applied to the upload")
 	insertCmd.Flags().BoolVarP(
-		&notifySubscribers, "notifySubscribers", "n", true,
+		&notifySubscribers, "notifySubscribers", "N", true,
 		"Notify the channel subscribers about the new video",
 	)
 	insertCmd.Flags().BoolVarP(
diff --git a/cmd/video/list.go b/cmd/video/list.go
index 4faa8f1..8709f25 100644
--- a/cmd/video/list.go
+++ b/cmd/video/list.go
@@ -38,11 +38,11 @@ func init() {
 		&chart, "chart", "c", "", "chartUnspecified or mostPopular",
 	)
 	listCmd.Flags().StringVarP(
-		&hl, "hl", "L", "", "Specifies the localization language",
+		&hl, "hl", "l", "", "Specifies the localization language",
 	)
-	listCmd.Flags().StringVarP(&locale, "locale", "l", "", "")
+	listCmd.Flags().StringVarP(&locale, "locale", "L", "", "")
 	listCmd.Flags().StringVarP(
-		&categoryId, "videoCategoryId", "v", "",
+		&categoryId, "videoCategoryId", "g", "",
 		"Specific to the specified video category",
 	)
 	listCmd.Flags().StringVarP(
@@ -62,7 +62,7 @@ func init() {
 		"Return videos liked/disliked by the authenticated user",
 	)
 	listCmd.Flags().StringVarP(
-		&output, "output", "o", "", "Output format: json or yaml",
+		&output, "output", "o", "", "json or yaml",
 	)
 	listCmd.Flags().StringArrayVarP(
 		&parts, "parts", "p", []string{"id", "snippet", "status"}, "Comma separated parts",
diff --git a/cmd/video/reportAbuse.go b/cmd/video/reportAbuse.go
index 7d32614..864850d 100644
--- a/cmd/video/reportAbuse.go
+++ b/cmd/video/reportAbuse.go
@@ -33,5 +33,5 @@ func init() {
 	)
 	reportAbuseCmd.Flags().StringVarP(&comments, "comments", "c", "", "Additional comments regarding the abuse report")
 	reportAbuseCmd.Flags().StringVarP(&language, "language", "l", "", "The language that the content was viewed in")
-	reportAbuseCmd.Flags().StringVarP(&onBehalfOfContentOwner, "onBehalfOfContentOwner", "o", "", "")
+	reportAbuseCmd.Flags().StringVarP(&onBehalfOfContentOwner, "onBehalfOfContentOwner", "b", "", "")
 }
diff --git a/cmd/video/update.go b/cmd/video/update.go
index ad33f12..d7233c4 100644
--- a/cmd/video/update.go
+++ b/cmd/video/update.go
@@ -46,7 +46,7 @@ func init() {
 		&license, "license", "L", "youtube", "youtube(default) or creativeCommon",
 	)
 	updateCmd.Flags().StringVarP(
-		&thumbnail, "thumbnail", "T", "", "Path to the thumbnail file",
+		&thumbnail, "thumbnail", "u", "", "Path to the thumbnail file",
 	)
 	updateCmd.Flags().StringVarP(
 		&playListId, "playlistId", "y", "", "Playlist ID of the video",
@@ -59,7 +59,7 @@ func init() {
 		"Privacy status of the video: public, private or unlisted",
 	)
 	updateCmd.Flags().BoolVarP(
-		&embeddable, "embeddable", "e", true, "Whether the video is embeddable",
+		&embeddable, "embeddable", "E", true, "Whether the video is embeddable",
 	)
 	updateCmd.Flags().StringVarP(&output, "output", "o", "", "json, yaml or silent")
 
diff --git a/cmd/videoAbuseReportReason/list.go b/cmd/videoAbuseReportReason/list.go
index 922999e..ff21ad1 100644
--- a/cmd/videoAbuseReportReason/list.go
+++ b/cmd/videoAbuseReportReason/list.go
@@ -28,6 +28,6 @@ func init() {
 		&parts, "parts", "p", []string{"id", "snippet"}, "Comma separated parts",
 	)
 	listCmd.Flags().StringVarP(
-		&output, "output", "o", "", "Output format: json or yaml",
+		&output, "output", "o", "", "json or yaml",
 	)
 }
diff --git a/cmd/videoCategory/list.go b/cmd/videoCategory/list.go
index fb5b28a..1adc819 100644
--- a/cmd/videoCategory/list.go
+++ b/cmd/videoCategory/list.go
@@ -30,6 +30,6 @@ func init() {
 		&parts, "parts", "p", []string{"id", "snippet"}, "Comma separated parts",
 	)
 	listCmd.Flags().StringVarP(
-		&output, "output", "o", "", "Output format: json or yaml",
+		&output, "output", "o", "", "json or yaml",
 	)
 }
diff --git a/cmd/watermark/set.go b/cmd/watermark/set.go
index 3ae1acf..4908e29 100644
--- a/cmd/watermark/set.go
+++ b/cmd/watermark/set.go
@@ -27,7 +27,7 @@ var setCmd = &cobra.Command{
 func init() {
 	wartermarkCmd.AddCommand(setCmd)
 
-	setCmd.Flags().StringVarP(&channelId, "channelId", "i", "", "ID of channel to set watermark")
+	setCmd.Flags().StringVarP(&channelId, "channelId", "c", "", "ID of channel to set watermark")
 	setCmd.Flags().StringVarP(&file, "file", "f", "", "Path to the watermark file")
 	setCmd.Flags().StringVarP(
 		&inVideoPosition, "inVideoPosition", "p", "", "topLeft, topRight, bottomLeft or bottomRight",
@@ -35,7 +35,7 @@ func init() {
 	setCmd.Flags().Uint64VarP(
 		&durationMs, "durationMs", "d", 0, "Duration in milliseconds for which the watermark should be displayed",
 	)
-	setCmd.Flags().Uint64VarP(&offsetMs, "offsetMs", "o", 0, "Defines the time at which the watermark will appear")
+	setCmd.Flags().Uint64VarP(&offsetMs, "offsetMs", "m", 0, "Defines the time at which the watermark will appear")
 	setCmd.Flags().StringVarP(&offsetType, "offsetType", "t", "", "offsetFromStart or offsetFromEnd")
 	setCmd.Flags().StringVarP(&onBehalfOfContentOwner, "onBehalfOfContentOwner", "b", "", "")
 
diff --git a/cmd/watermark/unset.go b/cmd/watermark/unset.go
index f84a1c6..e4a3867 100644
--- a/cmd/watermark/unset.go
+++ b/cmd/watermark/unset.go
@@ -21,6 +21,6 @@ var unsetCmd = &cobra.Command{
 func init() {
 	wartermarkCmd.AddCommand(unsetCmd)
 
-	unsetCmd.Flags().StringVarP(&channelId, "channelId", "i", "", "ID of the channel to set watermark")
+	unsetCmd.Flags().StringVarP(&channelId, "channelId", "c", "", "ID of the channel to set watermark")
 	unsetCmd.MarkFlagRequired("channelId")
 }