shadow/man/chgpasswd.8.xml

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<?xml version="1.0" encoding="UTF-8"?>
<refentry id='chgpasswd.8'>
<!-- $Id$ -->
<refmeta>
<refentrytitle>chgpasswd</refentrytitle>
<manvolnum>8</manvolnum>
<refmiscinfo class="sectdesc">System Management Commands</refmiscinfo>
</refmeta>
<refnamediv id='name'>
<refname>chgpasswd</refname>
<refpurpose>update group passwords in batch mode</refpurpose>
</refnamediv>
<refsynopsisdiv id='synopsis'>
<cmdsynopsis>
<command>chgpasswd</command>
<arg choice='opt'>
<replaceable>options</replaceable>
</arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1 id='description'>
<title>DESCRIPTION</title>
<para>
The <command>chgpasswd</command> command reads a list of group name
and password pairs from standard input and uses this information to
update a set of existing groups. Each line is of the format:
</para>
<para>
<emphasis remap='I'>group_name</emphasis>:<emphasis
remap='I'>password</emphasis>
</para>
<para>
By default the supplied password must be in clear-text. Default
encryption algorithm is DES.
</para>
<para>
The default encryption algorithm can be defined for the system with
the ENCRYPT_METHOD variable of <filename>/etc/login.defs</filename>,
and can be overwiten with the <option>-e</option>,
<option>-m</option>, or <option>-c</option> options.
</para>
<para>
This command is intended to be used in a large system environment
where many accounts are created at a single time.
</para>
</refsect1>
<refsect1 id='options'>
<title>OPTIONS</title>
<para>
The options which apply to the <command>chgpasswd</command> command
are:
</para>
<variablelist remap='IP'>
<varlistentry>
<term><option>-c</option>, <option>--crypt-method</option></term>
<listitem>
<para>Use the specified method to encrypt the passwords.</para>
<para>
The available methods are DES, MD5, and SHA256 or SHA512
if compiled with the ENCRYPTMETHOD_SELECT flag.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-e</option>, <option>--encrypted</option></term>
<listitem>
<para>Supplied passwords are in encrypted form.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-h</option>, <option>--help</option></term>
<listitem>
<para>Display help message and exit.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-m</option>, <option>--md5</option></term>
<listitem>
<para>
Use MD5 encryption instead of DES when the supplied passwords are
not encrypted.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-s</option>, <option>--sha-rounds</option></term>
<listitem>
<para>
Use the specified number of rounds to encrypt the passwords.
</para>
<para>
The value 0 means that the system will choose the default
number of rounds for the crypt method (5000).
</para>
<para>
A minimal value of 1000 and a maximal value of 999,999,999
will be enforced.
</para>
<para>
You can only use this option with the SHA256 or SHA512
crypt method.
</para>
<para>
By default, the number of rounds is defined by the
SHA_CRYPT_MIN_ROUNDS and SHA_CRYPT_MAX_ROUNDS variables in
<filename>/etc/login.defs</filename>.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id='caveats'>
<title>CAVEATS</title>
<para>
Remember to set permissions or umask to prevent readability of
unencrypted files by other users.
</para>
</refsect1>
<refsect1 id='see_also'>
<title>SEE ALSO</title>
<para>
<citerefentry>
<refentrytitle>gpasswd</refentrytitle><manvolnum>1</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>groupadd</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>login.defs</refentrytitle><manvolnum>5</manvolnum>
</citerefentry>.
</para>
</refsect1>
</refentry>