namespace export ?-clear? ?pattern pattern ...?
Specifies which commands are exported from a namespace. The exported commands are those that can be later imported into another namespace using a namespace import command. Both commands defined in a namespace and commands the namespace has previously imported can be exported by a namespace. The commands do not have to be defined at the time the namespace export command is executed. Each pattern may contain glob-style special characters, but it may not include any namespace qualifiers. That is, the pattern can only specify commands in the current (exporting) namespace. Each pattern is appended onto the namespace's list of export patterns. If the -clear flag is given, the namespace's export pattern list is reset to empty before any pattern arguments are appended. If no patterns are given and the -clear flag isn't given, this command returns the namespace's current export list.