To save the current mail message to a folder:
& s +usability "/usr/eucs/john/mrtidy/usability" [Appended]
This saves the current message to the folder usability, which is in the directory defined by the set folder variable. The message will be appended to the existing file. If the file does not exist, it is created.
To save several messages to the same file:
& s bob +frombob "/usr/eucs/john/mrtidy/frombob" [New file]
This saves all the messages from the user bob to the the folder frombob, which is in the directory defined by the set folder variable.
In this example the folder does not already exist, so it is created.