The mail folder files used by
Ishmail, in particular the
referred to as the "system folder," can be
shared with other
supported mail programs, such as
There are many different mail folder formats, but most UNIX mail tools use one of three different formats for the data in mail folders. Programs such as mail, mailx, and elm store mail folders as files, each file containing one or more mail messages. The name of the file is the name of the folder. A line starting with the characters "From" is considered the start of a new message.
The MMDF program also stores folders as a single file containing one or more messages. However, in MMDF-style folders a line containing four Ctrl-A characters at the beginning and end of each message is used to separate messages.
The mh program, and related tools such as xmh and exmh, use a directory as a mail folder. Mail messages are saved as individual files in the directory. The folder name is the directory name, and the names of the files in the directory are numbers corresponding to the mail message number.
Ishmail can work with any of these three mail folder types.
Ishmail's ability to share mail files with these other mail programs gives you the flexibility of accessing your mail folders via a "dial-up" modem connection from any remote location. In most cases, such dial-up modem connections are through character-mode mail programs such as elm, mh, mail, and mailx.
If you intend to use a character-mode interface to access your mail remotely through a dial-up connection to the host system on which your mail resides, you should save your changes to Ishmail before using the other mail interface. Otherwise you could lose unsaved changes.
You can make changes to your mail folders using another mail interface program such as mail or mailx while Ishmail is simultaneously running on your host system. If you do, the potential exists for some mail messages to get out of sync with the internal copies kept by Ishmail, possibly resulting in some "Read" messages reverting back to "New" status. Some previously deleted messages may also show up again in Ishmail.
As a safeguard against data loss, Ishmail detects changes in the status of open mail folders. The next time you use Ishmail, it will notify you with a pop-up window that a folder has been changed by another program. When that happens, Ishmail always rereads the folder file to get the most up-to-date copy. As a result, any changes you previously made while in Ishmail but didn't save will be lost.