PWCK(8)

名称
pwck - verify the integrity of password files

大纲

pwck [options] [PASSWORDFILE [ SHADOWFILE ]]

描述

The pwck command verifies the integrity of the users and authentication information. It checks that all entries in /etc/passwd and /etc/shadow have the proper format and contain valid data. The user is prompted to delete entries that are improperly formatted or which have other uncorrectable errors.

检查的项目有：

    • 正确的字段数

    • 一个唯一且有效的用户名

    • 一个有效的用户和组标识符

    • 有效的主组

    • 有效的主目录

    • 有效的登录 shell

Checks for shadowed password information are enabled when the second file parameter SHADOWFILE is specified or when /etc/shadow exists on the system.

这些检查是：

    • 每个密码项都有对应的影子相，反之亦然。

    • 密码在影子化了的文件中指定

    • 影子项有正确的字段数。

    • 影子项在影子文件中是唯一的

    • 最后一次的密码更改时间不是被设成了一个将来的时间。

The checks for correct number of fields and unique user name are fatal. If the entry has the wrong number of fields, the user will be prompted to delete the entire line. If the user does not answer affirmatively, all further checks are bypassed. An entry with a duplicated user name is prompted for deletion, but the remaining checks will still be made. All other errors are warnings and the user is encouraged to run the usermod command to correct the error.

The commands which operate on the /etc/passwd file are not able to alter corrupted or duplicated entries. pwck should be used in those circumstances to remove the offending entry.

选项

The -r and -s options cannot be combined.

The options which apply to the pwck command are:

--badname
    Allow names that do not conform to standards.

-h, --help
    显示帮助信息并退出。

-q, --quiet
    只报告错误。不显示那些不需要用户操作的警告。

-r, --read-only
    Execute the pwck command in read-only mode.

-R, --root CHROOT_DIR
    Apply changes in the CHROOT_DIR directory and use the configuration files from the CHROOT_DIR directory. Only absolute paths are supported. No SELINUX support.

-s, --sort
    Sort entries in /etc/passwd and /etc/shadow by UID.

By default, pwck operates on the files /etc/passwd and /etc/shadow. The user may select alternate files with the passwd and shadow parameters.

配置文件

The following configuration variables in /etc/login.defs change the behavior of this tool:

NONEXISTENT (string)
    If a system account intentionally does not have a home directory that exists, this string can be provided in the /etc/passwd entry for the account to indicate this. The result is that pwck will not emit a spurious warning for this account.

PASS_MAX_DAYS (number)
    The maximum number of days a password may be used. If the password is older than this, a password change will be forced. If not specified, -1 will be assumed (which disables the restriction).

PASS_MIN_DAYS (number)
    The minimum number of days allowed between password changes. Any password changes attempted sooner than this will be rejected. If not specified, 0 will be assumed (which disables the restriction).

PASS_WARN_AGE (number)
    The number of days warning given before a password expires. A zero means warning is given only upon the day of expiration, a value of -1 means no warning is given. If not specified, no warning will be provided.

文件

/etc/group
    组账户信息。

/etc/passwd
    用户账户信息。

/etc/shadow
    安全用户账户信息。

退出值

The pwck command exits with the following values:

0
    success

1
    invalid command syntax

2
    one or more bad password entries

3
    can't open password files

4
    can't lock password files

5
    can't update password files

6
    can't sort password files

参见

group(5), grpck(8), passwd(5), shadow(5), usermod(8).