[quote=[url=http://partmaps.org/era/procmail/mini-faq.html]procmail mini faq[/url]]MH format
    This is a one-message-per-file format, where a directory forms the folder and the files in it are messages (the only exceptions are control and cache files used by certain MUAs). The file names are numbers (not necessarily in sequence), or numbers preceded by commas. The files with names starting with commas correspond to deleted messages. 
    Procmail can deliver to MH directories but doesn't know how to update the associated control and cache files. For that reason, some people prefer to pipe messages to the MH rcvstore program instead of delivering straight to an MH folder. 
    Used by the Rand MH system and derivatives.[/quote]

see also [url=http://www.beedub.com/cgi-bin/wiki.cgi/27]here[/url]

apt-get install nmh

cat >~/.mh_profile
Path: /home/meillo/Mail
Unseen-Sequence: unseen
^D

vim ~/.procmailrc
add:
STORE=/usr/lib/mh/rcvstore
LOCK=.lock

this:
:0
* @lists.debian.org
$MAILDIR/Computer/Debian/.

is now:
:0 w :$LOCK
* @lists.debian.org
| $STORE +Computer/Debian