redhat man page for qmail-getpw

qmail-getpw(8)                                                System Manager's Manual                                               qmail-getpw(8)

NAME
       qmail-getpw - give addresses to users

SYNOPSIS
       qmail-getpw local

DESCRIPTION
       In  qmail,  each  user controls a vast array of local addresses.  qmail-getpw finds the user that controls a particular address, local.  It
       prints six pieces of information, each terminated by NUL: user; uid; gid; homedir; dash; and ext.  The user's account  name  is  user;  the
       user's  uid  and  gid  in  decimal  are  uid  and gid; the user's home directory is homedir; and messages to local will be handled by home-
       dir/.qmaildashext.

       In case of trouble, qmail-getpw exits nonzero without printing anything.

       WARNING: The operating system's getpwnam function, which is at the heart of qmail-getpw, is inherently unreliable: it fails to  distinguish
       between  temporary  errors and nonexistent users.  Future versions of getpwnam should return ETXTBSY to indicate temporary errors and ESRCH
       to indicate nonexistent users.

RULES
       qmail-getpw considers an account in /etc/passwd to be a user if (1) the account has a nonzero uid, (2) the account's home directory  exists
       (and  is visible to qmail-getpw), and (3) the account owns its home directory.  qmail-getpw ignores account names containing uppercase let-
       ters.  qmail-getpw also assumes that all account names are shorter than 32 characters.

       qmail-getpw gives each user control over the basic user address and all addresses of the form user-anything.  When local is user, dash  and
       ext  are  both  empty.  When local is user-anything, dash is a hyphen and ext is anything.  user may appear in any combination of uppercase
       and lowercase letters at the front of local.

       A catch-all user, alias, controls all other addresses.  In this case ext is local and dash is a hyphen.

       You can override all of qmail-getpw's decisions with the qmail-users mechanism, which is reliable, highly  configurable,  and  much  faster
       than qmail-getpw.

SEE ALSO
       qmail-users(5), qmail-lspawn(8)

                                                                                                                                    qmail-getpw(8)