drwxrwx---   2 cyrus shadowers 4.0K Oct 16 18:00 .
drwxr-x---  16 cyrus mail      4.0K Oct 16 18:00 ..
-rw-------   1 cyrus mail         0 Oct 16 10:43 imap-0.lock
-rw-------   1 cyrus mail         0 Oct 16 10:43 imap-1.lock
-rw-------   1 cyrus mail         0 Oct 16 10:43 imaps-0.lock
-rw-------   1 cyrus mail         0 Oct 16 10:43 imaps-1.lock
srwxrwxrwx   1 root  shadowers    0 Oct 16 18:00 lmtp
-rw-------   1 cyrus mail         0 Oct 16 10:43 lmtpunix-0.lock
-rw-------   1 cyrus mail         0 Oct 16 10:43 pop3-0.lock
-rw-------   1 cyrus mail         0 Oct 16 10:43 pop3-1.lock
-rw-------   1 cyrus mail         0 Oct 16 10:43 pop3s-0.lock
-rw-------   1 cyrus mail         0 Oct 16 10:43 pop3s-1.lock

[root@chrisnux socket]# id cyrus
uid=505(cyrus) gid=507(cyrus) groups=507(cyrus),506(virtman)

[root@chrisnux socket]# id postfix
uid=89(postfix) gid=505(shadowers) groups=505(shadowers),89(postfix)