/etc/passwd 文件内容详解

最新推荐文章于 2024-05-23 11:15:33 发布

iteye_887

最新推荐文章于 2024-05-23 11:15:33 发布

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文章标签： shell

本文深入探讨了Linux系统中的passwd文件，详细解释了其中各字段的含义，包括用户名、密码、用户ID、组ID、用户描述、主目录和登陆shell，并介绍了伪用户的概念及其在系统管理中的作用。

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<div>今天我看了一个文档，虽然是讲命令的，但是它用passwd 文件做的例子，由于许多天之前看过，现在有点忘记，所以现在拿出来恶补一下！！</div>
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<div>/etc/passwd 是存放用户的地方</div>
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<span style="background-color: #ff0000; font-size: small;">1 2 3 4 5 6 7 </span>
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<span style="font-size: large;">root: x : 0 : 0 : root : / root : / bin/bash<br><span style="font-size: small;">bin:x:1:1:bin:/bin:/sbin/nologin<br>
daemon:x:2:2:daemon:/sbin:/sbin/nologin<br>
adm:x:3:4:adm:/var/adm:/sbin/nologin<br>
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin<br>
sync:x:5:0:sync:/sbin:/bin/sync<br>
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown<br>
halt:x:7:0:halt:/sbin:/sbin/halt<br>
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin<br></span>
用户名: 密码 : uid : gid :用户描述：主目录：登陆shell</span>
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<span style="font-family: Arial; font-size: small;">UID : 每个用户必须被分配一个userid,”0”为root保留ID.</span>
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<span style="font-family: Arial; font-size: small;">1-99为系统保留,分配给系统预定义帐号.HP-UX10.20支持2 147 483 646. HP-UX10.20以前支持不大于60000个.</span>
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<span style="font-family: Arial; font-size: small;">系统中有一类用户称为伪用户（psuedo users），这些用户在/etc/passwd文件中也占有一条记录，但是不能登录，因为它们的登录Shell为空。它们的存在主要是方便系统管理，满足相应的系统进程对文件属主的要求。常见的伪用户如表8-1所示。</span>
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<span style="font-family: Arial; font-size: small;">　　表8-1 /etc/passwd文件中常见的伪用户</span>
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<table style="border-collapse: collapse;" border="0" cellspacing="0" cellpadding="0"><tbody>
<tr>
<td style="border-right: medium none #d4d0c8; padding: 0cm; width: 95.85pt;" width="128" valign="top">
<div class="a9" style="margin: 0cm 0cm 0pt;">
<span style="font-family: Arial;"><span style="" lang="AR-SA">伪</span>
<span lang="EN-US"><span> </span>
</span>
<span style="" lang="AR-SA">用</span>
<span lang="EN-US"><span> </span>
</span>
<span style="" lang="AR-SA">户</span>
</span>
</div>
</td>
<td style="border-right: medium none #d4d0c8; padding: 0cm; width: 163.45pt;" width="218" valign="top">
<div class="a9" style="margin: 0cm 0cm 0pt;">
<span style="font-family: Arial;"><span style="" lang="AR-SA">含</span>
<span lang="EN-US"><span> </span>
</span>
<span style="" lang="AR-SA">义</span>
</span>
</div>
</td>
</tr>
<tr>
<td style="border-right: medium none #d4d0c8; padding: 0cm 1.4pt; width: 95.85pt; background-color: transparent; border: medium none #d4d0c8;" width="128" valign="top">
<div class="aa" style="margin: 0cm 0cm 0pt 10.5pt;">
<span lang="EN-US"><span style="font-family: Arial;">bin</span>
</span>
</div>
</td>
<td style="border-right: medium none #d4d0c8; padding: 0cm 1.4pt; width: 163.45pt; background-color: transparent; border: medium none #d4d0c8;" width="218" valign="top">
<div class="aa" style="margin: 0cm 0cm 0pt 10.5pt;">
<span style="font-family: Arial;"><span style="">拥有可执行的用户命令文件</span>
</span>
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</td>
</tr>
<tr>
<td style="border-right: medium none #d4d0c8; padding: 0cm 1.4pt; width: 95.85pt; background-color: transparent; border: medium none #d4d0c8;" width="128" valign="top">
<div class="aa" style="margin: 0cm 0cm 0pt 10.5pt;">
<span lang="EN-US"><span style="font-family: Arial;">sys</span>
</span>
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</td>
<td style="border-right: medium none #d4d0c8; padding: 0cm 1.4pt; width: 163.45pt; background-color: transparent; border: medium none #d4d0c8;" width="218" valign="top">
<div class="aa" style="margin: 0cm 0cm 0pt 10.5pt;">
<span style="font-family: Arial;"><span style="">拥有系统文件</span>
</span>
</div>
</td>
</tr>
<tr>
<td style="border-right: medium none #d4d0c8; padding: 0cm 1.4pt; width: 95.85pt; background-color: transparent; border: medium none #d4d0c8;" width="128" valign="top">
<div class="aa" style="margin: 0cm 0cm 0pt 10.5pt;">
<span lang="EN-US"><span style="font-family: Arial;">adm</span>
</span>
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</td>
<td style="border-right: medium none #d4d0c8; padding: 0cm 1.4pt; width: 163.45pt; background-color: transparent; border: medium none #d4d0c8;" width="218" valign="top">
<div class="aa" style="margin: 0cm 0cm 0pt 10.5pt;">
<span style="font-family: Arial;"><span style="">拥有帐户文件</span>
</span>
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</td>
</tr>
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<td style="border-right: medium none #d4d0c8; padding: 0cm 1.4pt; width: 95.85pt; background-color: transparent; border: medium none #d4d0c8;" width="128" valign="top">
<div class="aa" style="margin: 0cm 0cm 0pt 10.5pt;">
<span lang="EN-US"><span style="font-family: Arial;">uucp</span>
</span>
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</td>
<td style="border-right: medium none #d4d0c8; padding: 0cm 1.4pt; width: 163.45pt; background-color: transparent; border: medium none #d4d0c8;" width="218" valign="top">
<div class="aa" style="margin: 0cm 0cm 0pt 10.5pt;">
<span style="font-family: Arial;"><span lang="EN-US">UUCP</span>
<span style="">使用</span>
</span>
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</td>
</tr>
<tr>
<td style="border-right: medium none #d4d0c8; padding: 0cm 1.4pt; width: 95.85pt; background-color: transparent; border: medium none #d4d0c8;" width="128" valign="top">
<div class="aa" style="margin: 0cm 0cm 0pt 10.5pt;">
<span lang="EN-US"><span style="font-family: Arial;">lp</span>
</span>
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</td>
<td style="border-right: medium none #d4d0c8; padding: 0cm 1.4pt; width: 163.45pt; background-color: transparent; border: medium none #d4d0c8;" width="218" valign="top">
<div class="aa" style="margin: 0cm 0cm 0pt 10.5pt;">
<span style="font-family: Arial;"><span lang="EN-US">lp</span>
<span style="">或</span>
<span lang="EN-US">lpd</span>
<span style="">子系统使用</span>
</span>
</div>
</td>
</tr>
<tr>
<td style="border-right: medium none #d4d0c8; padding: 0cm 1.4pt; width: 95.85pt; background-color: transparent;" width="128" valign="top">
<div class="aa" style="margin: 0cm 0cm 0pt 10.5pt;">
<span lang="EN-US"><span style="font-family: Arial;">nobody</span>
</span>
</div>
</td>
<td style="border-right: medium none #d4d0c8; padding: 0cm 1.4pt; width: 163.45pt; background-color: transparent;" width="218" valign="top">
<div class="aa" style="margin: 0cm 0cm 0pt 10.5pt;">
<span style="font-family: Arial;"><span lang="EN-US">NFS</span>
<span style="">使用</span>
</span>
</div>
</td>
</tr>
</tbody></table>
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<span style="font-family: Arial; font-size: small;">　　除了上面列出的伪用户外，还有许多标准的伪用户，例如：audit, cron, mail, usenet等，它们也都各自为相关的进程和文件所需要。</span>
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<span style="font-family: Arial; font-size: small;"><span style="font-family: Times New Roman;">/etc/shadow中的记录行与/etc/passwd中的一一对应，它由pwconv命令根据/etc/passwd中的数据自动产生。它的文件格式与/etc/passwd类似，由若干个字段组成，字段之间用“:”隔开。这些字段是：</span>
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<p><span style="font-family: Arial; font-size: small;">
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<div>登录名:加密口令:最后一次修改时间:最小时间间隔:最大时间间隔:警告时间:不活动时间:</div>
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