adding a private field to flags, and a function for marking flags as private

removing some c/p left-overs from the MarkPrivate function, and updating the comment slightly

changed field from Private to Hidden. Added documentation w/example to README.md. Added testing to confirm hidden flags

updating test message

1 files changed, 18 insertions, 9 deletions

diff --git a/README.md b/README.md
index 247ceca..e74dd50 100644
--- a/README.md
+++ b/README.md
@@ -216,24 +216,33 @@ func aliasNormalizeFunc(f *pflag.FlagSet, name string) pflag.NormalizedName {
 myFlagSet.SetNormalizeFunc(aliasNormalizeFunc)
 ```
 
-## Deprecating a flag or its shorthand 
-It is possible to deprecate a flag, or just its shorthand. Deprecating a flag/shorthand hides it from help text and prints a usage message when the deprecated flag/shorthand is used. 
+## Deprecating a flag or its shorthand
+It is possible to deprecate a flag, or just its shorthand. Deprecating a flag/shorthand hides it from help text and prints a usage message when the deprecated flag/shorthand is used.
 
-**Example #1**: You want to deprecate a flag named "badflag" as well as inform the users what flag they should use instead. 
+**Example #1**: You want to deprecate a flag named "badflag" as well as inform the users what flag they should use instead.
 ```go
-// deprecate a flag by specifying its name and a usage message 
+// deprecate a flag by specifying its name and a usage message
 flags.MarkDeprecated("badflag", "please use --good-flag instead")
 ```
-This hides "badflag" from help text, and prints `Flag --badflag has been deprecated, please use --good-flag instead` when "badflag" is used. 
+This hides "badflag" from help text, and prints `Flag --badflag has been deprecated, please use --good-flag instead` when "badflag" is used.
 
-**Example #2**: You want to keep a flag name "noshorthandflag" but deprecate its shortname "n". 
+**Example #2**: You want to keep a flag name "noshorthandflag" but deprecate its shortname "n".
 ```go
-// deprecate a flag shorthand by specifying its flag name and a usage message 
+// deprecate a flag shorthand by specifying its flag name and a usage message
 flags.MarkShorthandDeprecated("noshorthandflag", "please use --noshorthandflag only")
 ```
-This hides the shortname "n" from help text, and prints `Flag shorthand -n has been deprecated, please use --noshorthandflag only` when the shorthand "n" is used. 
+This hides the shortname "n" from help text, and prints `Flag shorthand -n has been deprecated, please use --noshorthandflag only` when the shorthand "n" is used.
 
-Note that usage message is essential here, and it should not be empty. 
+Note that usage message is essential here, and it should not be empty.
+
+## Hidden flags
+It is possible to mark a flag as hidden, meaning it will still function as normal, however will not show up in usage/help text.
+
+**Example**: You have a flag named "secretFlag" that you need for internal use only and don't want it showing up in help text, or for its usage text to be available.
+```go
+// hide a flag by specifying its name
+flags.MarkHidden("secretFlag")
+```
 
 ## More info