修改/etc/default/passwd可修改创建用户密码的规则，如密码长度、是否需要特殊字符等。
# cat /etc/default/passwd MAXWEEKS= //最大保存日期，多少周后密码失效 MINWEEKS= //最小保存日期，多少周后可再次修改密码 WARNWEEKS= //修改口令后第三个星期会收到快要修改口令的信息 PASSLENGTH=6 //密码长度限制 # NAMECHECK enables/disables login name checking. # The default is to do login name checking. # Specifying a value of "NO" will disable login name checking. # #NAMECHECK=NO //不能和用户名相同 # # HISTORY sets the number of prior password changes to keep and # check for a user when changing passwords. Setting the HISTORY # value to zero (0), or removing/commenting out the flag will # cause all users' prior password history to be discarded at the # next password change by any user. No password history will # be checked if the flag is not present or has zero value. # The maximum value of HISTORY is 26. # # This flag is only enforced for user accounts defined in the # local passwd(4)/shadow(4) files. # #HISTORY=0 //修改密码时进行历史检查，不能改成和以前一样的 # # Password complexity tunables. The values listed are the defaults # which are compatible with previous releases of passwd. # See passwd(1) and pam_authtok_check(5) for use warnings and # discussion of the use of these options. # #MINDIFF=3 #MINALPHA=2 #MINNONALPHA=1 #MINUPPER=0 #MINLOWER=0 #MAXREPEATS=0 #MINSPECIAL=0 #MINDIGIT=0 #WHITESPACE=YES # # passwd performs dictionary lookups if DICTIONLIST or DICTIONDBDIR # is defined. If the password database does not yet exist, it is # created by passwd. See passwd(1), pam_authtok_check(5) and # mkdict(1) for more information. # #DICTIONLIST= #DICTIONDBDIR=/var/passwd