Directory structure of Qmail :-

[root@ds1130 var]# tree qmail/ | grep [a-zA-Z]
qmail/
|-- alias
|-- bin
| |-- autoresponder
| |-- bouncesaying
| |-- cmd5checkpw
| |-- condredirect
| |-- datemail
| |-- elq
| |-- except
| |-- forward
| |-- maildir2mbox
| |-- maildirmake
| |-- maildirwatch
| |-- mailsubj
| |-- matchup
| |-- mm_wrapper
| |-- pinq
| |-- predate
| |-- preline
| |-- qail
| |-- qbiff
| |-- qmail-clean
| |-- qmail-dk
| |-- qmail-getpw
| |-- qmail-inject
| |-- qmail-local
| |-- qmail-local.moved
| |-- qmail-local.plesk
| |-- qmail-lspawn
| |-- qmail-newmrh
| |-- qmail-newu
| |-- qmail-pop3d
| |-- qmail-popup
| |-- qmail-pw2u
| |-- qmail-qmqpc
| |-- qmail-qmqpd
| |-- qmail-qmtpd
| |-- qmail-qread
| |-- qmail-qstat
| |-- qmail-queue
| |-- qmail-queue.drweb
| |-- qmail-queue.moved
| |-- qmail-queue.origin
| |-- qmail-queue.plesk
| |-- qmail-remote
| |-- qmail-remote.moved
| |-- qmail-remote.plesk
| |-- qmail-rspawn
| |-- qmail-send
| |-- qmail-showctl
| |-- qmail-smtpd
| |-- qmail-start
| |-- qmail-tcpok
| |-- qmail-tcpto
| |-- qreceipt
| |-- qsmhook
| |-- relaylock
| |-- sendmail
| |-- smtp_auth
| |-- splogger
| |-- tcp-env
| `-- true
|-- boot
| |-- binm1
| |-- binm1+df
| |-- binm2
| |-- binm2+df
| |-- binm3
| |-- binm3+df
| |-- home
| |-- home+df
| |-- proc
| `-- proc+df
|-- control
| |-- clientcert.pem -> /var/qmail/control/servercert.pem
| |-- defaultdelivery
| |-- dhparam1024.pem
| |-- dhparam512.pem
| |-- locals
| |-- me
| |-- rcpthosts
| |-- rejectnonexist
| |-- rsa512.pem
| |-- servercert.pem
| |-- smtpplugins
| |-- spfrules
| `-- virtualdomains
|-- handlers
| |-- before-local
| |-- before-queue
| |-- before-remote
| |-- info
| `-- spool
|-- mailnames
| `-- energy.com.pa
| `-- alex
| |-- @attachments
| `-- Maildir
| |-- cur
| |-- maildirsize
| |-- new
| `-- tmp
|-- plugins
| `-- chkrcptto
|-- queue
| |-- bounce
| |-- info
| |-- intd
| |-- local
| |-- lock
| | |-- sendmutex
| | |-- tcpto
| | `-- trigger
| |-- mess
| |-- pid
| |-- remote
| `-- todo
`-- users
|-- assign
|-- cdb
`-- poppasswd
168 directories, 2089 files
[root@ds1130 var]