save <file name>
e.g. save $home/mail/bookfolder
This causes a copy of the message to be appended to the given file (that is, the file is used as a mail folder). More than one save command may appear; each one causes a copy of the message to be written to its argument file, provided they are different (duplicate save commands are ignored).
If the file name does not start with a / character, the contents of the $home variable are prepended. In conventional configurations, this variable is normally set in a user filter. However, it is never set in a system filter.
The user must of course have permission to write to the file, and the writing of the file takes place in a process that is running as the user, under the user's primary group. Any secondary groups to which the user may belong are not normally taken into account, though the system administrator can configure Exim to set them up. In addition, the ability to use this command at all is controlled by the system administrator - it may be forbidden on some systems.
An optional mode value may be given after the file name. The value for the mode is interpreted as an octal number, even if it does not begin with a zero. For example:
save /some/folder 640
This makes it possible for users to override the system-wide mode setting for file deliveries, which is normally 600. If an existing file does not have the correct mode, it is changed.
An alternative form of delivery may be enabled on your system, in which each message is delivered into a new file in a given directory. If this is the case, this functionality can be requested by giving the directory name terminated by a slash after the save command, for example
save separated/messages/
There are several different formats for such deliveries; check with your system administrator or local documentation to find out which (if any) are available on your system. If this functionality is not enabled, the use of a path name ending in a slash causes an error.