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| <html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>passwd</title><link rel="stylesheet" type="text/css" href="docbook.css"><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot"><link rel="home" href="cygwin-ug-net.html" title="Cygwin User's Guide"><link rel="up" href="using-utils.html" title="Cygwin Utilities"><link rel="prev" href="newgrp.html" title="newgrp"><link rel="next" href="pldd.html" title="pldd"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">passwd</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="newgrp.html">Prev</a> </td><th width="60%" align="center">Cygwin Utilities</th><td width="20%" align="right"> <a accesskey="n" href="pldd.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="passwd"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>passwd — Change password or password attributes</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="cmdsynopsis"><p><code class="command">passwd</code> [-S] | { |
| [ -l | -u ] |
| [ -c | -C ] |
| [ -e | -E ] |
| [ -p | -P ] |
| } [-d <em class="replaceable"><code>SERVER</code></em>] [<em class="replaceable"><code>USER</code></em>]</p></div><div class="cmdsynopsis"><p><code class="command">passwd</code> -R </p></div><div class="cmdsynopsis"><p><code class="command">passwd</code> -i <em class="replaceable"><code>NUM</code></em> | -n <em class="replaceable"><code>MINDAYS</code></em> | -x <em class="replaceable"><code>MAXDAYS</code></em> | -L <em class="replaceable"><code>LEN</code></em> </p></div><div class="cmdsynopsis"><p><code class="command">passwd</code> -h | -V </p></div></div><div class="refsect1"><a name="passwd-options"></a><h2>Options</h2><pre class="screen"> |
| User operations: |
| -l, --lock lock USER's account. |
| -u, --unlock unlock USER's account. |
| -c, --cannot-change USER can't change password. |
| -C, --can-change USER can change password. |
| -e, --never-expires USER's password never expires. |
| -E, --expires USER's password expires according to system's |
| password aging rule. |
| -p, --pwd-not-required no password required for USER. |
| -P, --pwd-required password is required for USER. |
| -R, --reg-store-pwd enter password to store it in the registry for |
| later usage by services to be able to switch |
| to this user context with network credentials. |
|
|
| System operations: |
| -i, --inactive NUM set NUM of days before inactive accounts are disabled |
| (inactive accounts are those with expired passwords). |
| -n, --minage MINDAYS set system minimum password age to MINDAYS days. |
| -x, --maxage MAXDAYS set system maximum password age to MAXDAYS days. |
| -L, --length LEN set system minimum password length to LEN. |
|
|
| Other options: |
| -d, --logonserver SERVER connect to SERVER (e.g. domain controller). |
| Usually not required. |
| -S, --status display password status for USER (locked, expired, |
| etc.) plus global system password settings. |
| -h, --help output usage information and exit. |
| -V, --version output version information and exit. |
|
|
| If no option is given, change USER's password. If no user name is given, |
| operate on current user. System operations must not be mixed with user |
| operations. Don't specify a USER when triggering a system operation. |
|
|
| Don't specify a user or any other option together with the -R option. |
| Non-Admin users can only store their password if cygserver is running. |
| Note that storing even obfuscated passwords in the registry is not overly |
| secure. Use this feature only if the machine is adequately locked down. |
| Don't use this feature if you don't need network access within a remote |
| session. You can delete your stored password by using `passwd -R' and |
| specifying an empty password. |
| </pre></div><div class="refsect1"><a name="passwd-desc"></a><h2>Description</h2><p> <span class="command"><strong>passwd</strong></span> changes passwords for user accounts. A |
| normal user may only change the password for their own account, but |
| administrators may change passwords on any account. |
| <span class="command"><strong>passwd</strong></span> also changes account information, such as |
| password expiry dates and intervals.</p><p>For password changes, the user is first prompted for their old |
| password, if one is present. This password is then encrypted and compared |
| against the stored password. The user has only one chance to enter the |
| correct password. The administrators are permitted to bypass this step so |
| that forgotten passwords may be changed.</p><p>The user is then prompted for a replacement password. |
| <span class="command"><strong>passwd</strong></span> will prompt twice for this replacement and |
| compare the second entry against the first. Both entries are required to |
| match in order for the password to be changed.</p><p>After the password has been entered, password aging information is |
| checked to see if the user is permitted to change their password at this |
| time. If not, <span class="command"><strong>passwd</strong></span> refuses to change the password |
| and exits.</p><p> To get current password status information, use the |
| <code class="literal">-S</code> option. Administrators can use |
| <span class="command"><strong>passwd</strong></span> to perform several account maintenance |
| functions (users may perform some of these functions on their own |
| accounts). Accounts may be locked with the <code class="literal">-l</code> flag and |
| unlocked with the <code class="literal">-u</code> flag. Similarly, |
| <code class="literal">-c</code> disables a user's ability to change passwords, and |
| <code class="literal">-C</code> allows a user to change passwords. For password |
| expiry, the <code class="literal">-e</code> option disables expiration, while the |
| <code class="literal">-E</code> option causes the password to expire according to |
| the system's normal aging rules. Use <code class="literal">-p</code> to disable the |
| password requirement for a user, or <code class="literal">-P</code> to require a |
| password. </p><p>Administrators can also use <span class="command"><strong>passwd</strong></span> to change |
| system-wide password expiry and length requirements with the |
| <code class="literal">-i</code>, <code class="literal">-n</code>, <code class="literal">-x</code>, and |
| <code class="literal">-L</code> options. The <code class="literal">-i</code> option is used |
| to disable an account after the password has been expired for a number of |
| days. After a user account has had an expired password for |
| <span class="emphasis"><em>NUM</em></span> days, the user may no longer sign on to the |
| account. The <code class="literal">-n</code> option is used to set the minimum |
| number of days before a password may be changed. The user will not be |
| permitted to change the password until <span class="emphasis"><em>MINDAYS</em></span> days |
| have elapsed. The <code class="literal">-x</code> option is used to set the maximum |
| number of days a password remains valid. After |
| <span class="emphasis"><em>MAXDAYS</em></span> days, the password is required to be |
| changed. Allowed values for the above options are 0 to 999. The |
| <code class="literal">-L</code> option sets the minimum length of allowed passwords |
| for users who don't belong to the administrators group to |
| <span class="emphasis"><em>LEN</em></span> characters. Allowed values for the minimum |
| password length are 0 to 14. In any of the above cases, a value of 0 |
| means `no restrictions'.</p><p> All operations affecting the current user are by default run against |
| the logon server of the current user (taken from the environment variable |
| <code class="envar">LOGONSERVER</code>. When password or account information of other |
| users should be changed, the logon server is evaluated automatically. |
| In rare cases, it might be necessary to switch to another domain |
| controller to perform the action. In this case, use the |
| <code class="literal">-d</code> option to specify the machine to run the command |
| against. Note that the current user must have account operator permissions |
| to perform user account changes in a domain. </p><p>Users can use the <span class="command"><strong>passwd -R</strong></span> to enter a password |
| which then gets stored in a special area of the registry on the local |
| system, which is also used by Windows to store passwords of accounts |
| running Windows services. When a privileged Cygwin application calls the |
| <span class="command"><strong>set{e}uid(user_id)</strong></span> system call, Cygwin checks if a |
| password for that user has been stored in this registry area. If so, it |
| uses this password to switch to this user account using that password. |
| This allows you to logon through, for instance, <span class="command"><strong>ssh</strong></span> |
| with public key authentication and get a full qualified user token with |
| all credentials for network access. However, the method has some |
| drawbacks security-wise. This is explained in more detail in <a class="xref" href="ntsec.html" title="POSIX accounts, permission, and security">the section called “POSIX accounts, permission, and security”</a>.</p><p>Please note that storing passwords in that registry area is a |
| privileged operation which only administrative accounts are allowed to |
| do. Administrators can enter the password for other user accounts into |
| the registry by specifying the username on the commandline. If normal, |
| non-admin users should be allowed to enter their passwords using |
| <span class="command"><strong>passwd -R</strong></span>, it's required to run |
| <span class="command"><strong>cygserver</strong></span> as a service under the LocalSystem account |
| before running <span class="command"><strong>passwd -R</strong></span>. This only affects storing |
| passwords. Using passwords in privileged processes does not require |
| <span class="command"><strong>cygserver</strong></span> to run.</p><p>Limitations: Users may not be able to change their password on some |
| systems.</p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="newgrp.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="using-utils.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="pldd.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">newgrp </td><td width="20%" align="center"><a accesskey="h" href="cygwin-ug-net.html">Home</a></td><td width="40%" align="right" valign="top"> pldd</td></tr></table></div></body></html> |
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