qmail-getpw - give addresses to users qmail-getpw local 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 homedir/.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. 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 letters. 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 userBREAKanything . When local is user , dash and ext are both empty. When local is userBREAKanything , 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 . qmail-users(5), qmail-lspawn(8)