shadow/man/passwd.5.xml
2021-03-12 23:56:38 +00:00

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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
<!-- SHADOW-CONFIG-HERE -->
]>
<refentry id='passwd.5'>
<!-- $Id$ -->
<refentryinfo>
<author>
<firstname>Julianne Frances</firstname>
<surname>Haugh</surname>
<contrib>Creation, 1989</contrib>
</author>
<author>
<firstname>Thomas</firstname>
<surname>Kłoczko</surname>
<email>kloczek@pld.org.pl</email>
<contrib>shadow-utils maintainer, 2000 - 2007</contrib>
</author>
<author>
<firstname>Nicolas</firstname>
<surname>François</surname>
<email>nicolas.francois@centraliens.net</email>
<contrib>shadow-utils maintainer, 2007 - now</contrib>
</author>
</refentryinfo>
<refmeta>
<refentrytitle>passwd</refentrytitle>
<manvolnum>5</manvolnum>
<refmiscinfo class="sectdesc">File Formats and Conversions</refmiscinfo>
<refmiscinfo class="source">shadow-utils</refmiscinfo>
<refmiscinfo class="version">&SHADOW_UTILS_VERSION;</refmiscinfo>
</refmeta>
<refnamediv id='name'>
<refname>passwd</refname>
<refpurpose>the password file</refpurpose>
</refnamediv>
<refsect1 id='description'>
<title>DESCRIPTION</title>
<para>
<filename>/etc/passwd</filename> contains one line for each
user account, with seven fields delimited by colons
(<quote>:</quote>).
These fields are:
</para>
<itemizedlist mark='bullet'>
<listitem>
<para>login name</para>
</listitem>
<listitem>
<para>optional encrypted password</para>
</listitem>
<listitem>
<para>numerical user ID</para>
</listitem>
<listitem>
<para>numerical group ID</para>
</listitem>
<listitem>
<para>user name or comment field</para>
</listitem>
<listitem>
<para>user home directory</para>
</listitem>
<listitem>
<para>optional user command interpreter</para>
</listitem>
</itemizedlist>
<para>
If the <emphasis>password</emphasis> field is a lower-case
<quote>x</quote>, then the encrypted password is actually stored in the
<citerefentry><refentrytitle>shadow</refentrytitle>
<manvolnum>5</manvolnum></citerefentry> file instead; there
<emphasis>must</emphasis> be a corresponding line in the
<filename>/etc/shadow</filename> file, or else the user account is invalid.
</para>
<para>
The encrypted <emphasis>password</emphasis> field may be empty,
in which case no password is required to authenticate as the
specified login name. However, some applications which read the
<filename>/etc/passwd</filename> file may decide not to permit
<emphasis>any</emphasis> access at all if the
<emphasis>password</emphasis> field is blank.
</para>
<para>
A <emphasis>password</emphasis> field which starts with an
exclamation mark means that the password is locked. The
remaining characters on the line represent the
<emphasis>password</emphasis> field before the password was
locked.
</para>
<para>
Refer to <citerefentry><refentrytitle>crypt</refentrytitle>
<manvolnum>3</manvolnum></citerefentry> for details on how
this string is interpreted.
</para>
<para>
If the password field contains some string that is not a valid
result of <citerefentry><refentrytitle>crypt</refentrytitle>
<manvolnum>3</manvolnum></citerefentry>, for instance ! or *,
the user will not be able to use a unix password to log in
(but the user may log in the system by other means).
</para>
<para>
The comment field, also known as the gecos field, is used by
various system utilities, such as
<citerefentry><refentrytitle>finger</refentrytitle>
<manvolnum>1</manvolnum></citerefentry>. The use of an ampersand
here will be replaced by the capitalised login name when the field
is used or displayed by such system utilities.
</para>
<para>
The home directory field provides the name of the initial working
directory. The <command>login</command> program uses this information
to set the value of the <envar>$HOME</envar> environmental variable.
</para>
<para>
The command interpreter field provides the name of the user's command
language interpreter, or the name of the initial program to execute.
The <command>login</command> program uses this information to set the
value of the <envar>$SHELL</envar> environmental variable. If this
field is empty, it defaults to the value <filename>/bin/sh</filename>.
</para>
</refsect1>
<refsect1 id='files'>
<title>FILES</title>
<variablelist>
<varlistentry>
<term><filename>/etc/passwd</filename></term>
<listitem>
<para>User account information.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>/etc/shadow</filename></term>
<listitem>
<para>optional encrypted password file</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>/etc/passwd-</filename></term>
<listitem>
<para>Backup file for /etc/passwd.</para>
<para>
Note that this file is used by the tools of the shadow
toolsuite, but not by all user and password management tools.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id='see_also'>
<title>SEE ALSO</title>
<para>
<citerefentry>
<refentrytitle>crypt</refentrytitle><manvolnum>3</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>getent</refentrytitle><manvolnum>1</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>getpwnam</refentrytitle><manvolnum>3</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>login</refentrytitle><manvolnum>1</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>passwd</refentrytitle><manvolnum>1</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>pwck</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>pwconv</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>pwunconv</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>shadow</refentrytitle><manvolnum>5</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>su</refentrytitle><manvolnum>1</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>sulogin</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>.
</para>
</refsect1>
</refentry>