参考: http://serverfault.com/questions/20702/how-do-i-create-user-accounts-from-the-terminal-in-mac-os-x-10-5

创建用户 "luser":
dscl . -create /Users/luser
dscl . -create /Users/luser UserShell /bin/bash
dscl . -create /Users/luser RealName "Lucius Q. User"
# 注意 UniqueID必须唯一
dscl . -create /Users/luser UniqueID "1010"
dscl . -create /Users/luser PrimaryGroupID 80
dscl . -create /Users/luser NFSHomeDirectory /Users/luser

修改密码:
dscl . -passwd /Users/luser password

加入admin用户组
dscl . -append /Groups/admin GroupMembership luser