'\" t
.\"     Title: pwconv
.\"    Author: Marek Micha\(/lkiewicz
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 2026-07-30
.\"    Manual: System Management Commands
.\"    Source: shadow-utils 4.20.0
.\"  Language: Chinese Simplified
.\"
.TH "PWCONV" "8" "2026-07-30" "shadow\-utils 4\&.20\&.0" "System Management Commands"
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.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
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.SH "名称"
pwconv, pwunconv, grpconv, grpunconv \- convert between the system\*(Aqs shadowed and plain account files
.SH "大纲"
.HP \w'\fBpwconv\fR\ 'u
\fBpwconv\fR [\fIoptions\fR]
.HP \w'\fBpwunconv\fR\ 'u
\fBpwunconv\fR [\fIoptions\fR]
.HP \w'\fBgrpconv\fR\ 'u
\fBgrpconv\fR [\fIoptions\fR]
.HP \w'\fBgrpunconv\fR\ 'u
\fBgrpunconv\fR [\fIoptions\fR]
.SH "描述"
.PP
The
\fBpwconv\fR
command creates
shadow
from
passwd
and an optionally existing
shadow\&.
.PP
The
\fBpwunconv\fR
command creates a plain
passwd
from shadowed
passwd
and
shadow
and then removes
shadow\&.
.PP
The
\fBgrpconv\fR
command creates
gshadow
from
group
and an optionally existing
gshadow\&.
.PP
The
\fBgrpunconv\fR
command creates plain
group
from shadowed
group
and
gshadow
and then removes
gshadow\&.
.PP
These four programs all operate on the normal and shadow password and group files:
/etc/passwd,
/etc/group,
/etc/shadow, and
/etc/gshadow\&.
.PP
Each program acquires the necessary locks before conversion\&.
\fBpwconv\fR
and
\fBgrpconv\fR
are similar\&. First, entries in the shadowed file which don\*(Aqt exist in the plain file are removed\&. Then, entries in the shadowed file which don\*(Aqt have `x\*(Aq as the password in plain file are updated\&. Any missing shadowed entries are added\&. Finally, passwords in the plain file are replaced with `x\*(Aq\&. These programs can be used for initial conversion as well to update the shadowed file if the plain file has been edited by hand\&.
.PP
\fBpwconv\fR
will use the values of
\fIPASS_MAX_DAYS\fR, and
\fIPASS_WARN_AGE\fR
from
/etc/login\&.defs
when adding new entries to
/etc/shadow\&.
.PP
Likewise
\fBpwunconv\fR
and
\fBgrpunconv\fR
are similar\&. Passwords in the plain file are updated from the shadowed file\&. Entries which exist in the plain file but not in the shadowed file are left alone\&. Finally, the shadowed file is removed\&. Some password aging information is lost by
\fBpwunconv\fR\&. It will convert what it can\&.
.SH "选项"
.PP
The options which apply to the
\fBpwconv\fR,
\fBpwunconv\fR,
\fBgrpconv\fR, and
\fBgrpunconv\fR
commands are:
.PP
\fB\-h\fR, \fB\-\-help\fR
.RS 4
显示帮助信息并退出。
.RE
.PP
\fB\-R\fR, \fB\-\-root\fR\ \&\fICHROOT_DIR\fR
.RS 4
Apply changes in the
\fICHROOT_DIR\fR
directory and use the configuration files from the
\fICHROOT_DIR\fR
directory\&. Only absolute paths are supported\&. No SELINUX support\&.
.RE
.SH "缺陷"
.PP
Errors in the password or group files (such as invalid or duplicate entries) may cause these programs to loop forever or fail in other strange ways\&. Please run
\fBpwck\fR
and
\fBgrpck\fR
to correct any such errors before converting to or from shadowed files\&.
.SH "配置文件"
.PP
The following configuration variable in
/etc/login\&.defs
changes the behavior of
\fBgrpconv\fR
and
\fBgrpunconv\fR:
.PP
\fBMAX_MEMBERS_PER_GROUP\fR (number)
.RS 4
Maximum members per group entry\&. When the maximum is reached, a new group entry (line) is started in
/etc/group
(with the same name, same password, and same GID)\&.
.sp
默认值是 0，意味着组中的成员数没有限制。
.sp
此功能(分割组)允许限制组文件中的行长度。这对于确保 NIS 组的行比长于 1024 字符。
.sp
如果要强制这个限制，可以使用 25。
.sp
注意：分割组可能不受所有工具的支持(甚至在 Shadow 工具集中)。您不应该使用这个变量，除非真的需要。
.RE
.PP
The following configuration variables in
/etc/login\&.defs
change the behavior of
\fBpwconv\fR:
.PP
\fBPASS_MAX_DAYS\fR (number)
.RS 4
一个密码可以使用的最大天数。如果密码比这旧，将会强迫更改密码。如果不指定，就假定为 \-1，这会禁用这个限制。
.RE
.PP
\fBPASS_WARN_AGE\fR (number)
.RS 4
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\&.
.RE
.SH "文件"
.PP
/etc/login\&.defs
.RS 4
Shadow 密码套件配置。
.RE
.SH "参见"
.PP
\fBgrpck\fR(8),
\fBlogin.defs\fR(5),
\fBpwck\fR(8)\&.