Remapping using namespaceless mappings from CLI?

[Lassebq]

usage: <input> <output> <mappings> <from> <to> [<classpath>]... [--reverse] [--forcePropagation=<file>] [--propagatePrivate] [--ignoreConflicts]

<from> and <to> arguments aren't optional, but what should you set them to when specifying mappings in a format that does not contain namespaces? For example proguard mappings.

[modmuss50]

The mappings will be assigned a namespace, I think its source and target, if not the error message says what namespaces you have.