##how to control visibility of menulets via terminal##

###on MacOS X 10.11 (and probably before):###

$ defaults read com.apple.systemuiserver

be cautious: in this command :menuExtra:1 refers to the second entry from the output of the previous command

$ /usr/libexec/PlistBuddy -c 'Delete :menuExtras:1' ~/Library/Preferences/com.apple.systemuiserver.plist
$ killall SystemUIServer

the second command needs to be applied multiple times, at least some times :-)