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<li><a class="reference internal" href="#">pwd – Unix Password Database</a><ul>
<li><a class="reference internal" href="#querying-all-users">Querying All Users</a></li>
<li><a class="reference internal" href="#querying-user-by-name">Querying User By Name</a></li>
<li><a class="reference internal" href="#querying-user-by-uid">Querying User By UID</a></li>
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<div class="section" id="module-pwd">
<span id="pwd-unix-password-database"></span><h1>pwd – Unix Password Database<a class="headerlink" href="#module-pwd" title="Permalink to this headline">¶</a></h1>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Purpose:</th><td class="field-body">Read user data from Unix password database.</td>
</tr>
<tr class="field"><th class="field-name">Python Version:</th><td class="field-body">1.4 and later</td>
</tr>
</tbody>
</table>
<p>The pwd module can be used to read user information from the Unix
password database (usually <tt class="docutils literal"><span class="pre">/etc/passwd</span></tt>). The read-only interface
returns tuple-like objects with named attributes for the standard
fields of a password record.</p>
<table border="1" class="docutils">
<colgroup>
<col width="7%" />
<col width="12%" />
<col width="81%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head">Index</th>
<th class="head">Attribute</th>
<th class="head">Meaning</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>0</td>
<td>pw_name</td>
<td>The user’s login name</td>
</tr>
<tr><td>1</td>
<td>pw_passwd</td>
<td>Encrypted password (optional)</td>
</tr>
<tr><td>2</td>
<td>pw_uid</td>
<td>User id (integer)</td>
</tr>
<tr><td>3</td>
<td>pw_gid</td>
<td>Group id (integer)</td>
</tr>
<tr><td>4</td>
<td>pw_gecos</td>
<td>Comment/full name</td>
</tr>
<tr><td>5</td>
<td>pw_dir</td>
<td>Home directory</td>
</tr>
<tr><td>6</td>
<td>pw_shell</td>
<td>Application started on login, usually a command interpreter</td>
</tr>
</tbody>
</table>
<div class="section" id="querying-all-users">
<h2>Querying All Users<a class="headerlink" href="#querying-all-users" title="Permalink to this headline">¶</a></h2>
<p>Suppose you need to print a report of all of the “real” users on a
system, including their home directories (for our purposes, “real” is
defined as having a name not starting with “<tt class="docutils literal"><span class="pre">_</span></tt>”). To load the
entire password database, you would use <tt class="docutils literal"><span class="pre">getpwall()</span></tt>. The return
value is a list with an undefined order, so you will need to sort it
before printing the report.</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">pwd</span>
<span class="kn">import</span> <span class="nn">operator</span>
<span class="c"># Load all of the user data, sorted by username</span>
<span class="n">all_user_data</span> <span class="o">=</span> <span class="n">pwd</span><span class="o">.</span><span class="n">getpwall</span><span class="p">()</span>
<span class="n">interesting_users</span> <span class="o">=</span> <span class="nb">sorted</span><span class="p">((</span><span class="n">u</span>
<span class="k">for</span> <span class="n">u</span> <span class="ow">in</span> <span class="n">all_user_data</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">u</span><span class="o">.</span><span class="n">pw_name</span><span class="o">.</span><span class="n">startswith</span><span class="p">(</span><span class="s">'_'</span><span class="p">)),</span>
<span class="n">key</span><span class="o">=</span><span class="n">operator</span><span class="o">.</span><span class="n">attrgetter</span><span class="p">(</span><span class="s">'pw_name'</span><span class="p">))</span>
<span class="c"># Find the longest lengths for a few fields</span>
<span class="n">username_length</span> <span class="o">=</span> <span class="nb">max</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">u</span><span class="o">.</span><span class="n">pw_name</span><span class="p">)</span> <span class="k">for</span> <span class="n">u</span> <span class="ow">in</span> <span class="n">interesting_users</span><span class="p">)</span> <span class="o">+</span> <span class="mi">1</span>
<span class="n">home_length</span> <span class="o">=</span> <span class="nb">max</span><span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">u</span><span class="o">.</span><span class="n">pw_dir</span><span class="p">)</span> <span class="k">for</span> <span class="n">u</span> <span class="ow">in</span> <span class="n">interesting_users</span><span class="p">)</span> <span class="o">+</span> <span class="mi">1</span>
<span class="c"># Print report headers</span>
<span class="n">fmt</span> <span class="o">=</span> <span class="s">'</span><span class="si">%-*s</span><span class="s"> </span><span class="si">%4s</span><span class="s"> </span><span class="si">%-*s</span><span class="s"> </span><span class="si">%s</span><span class="s">'</span>
<span class="k">print</span> <span class="n">fmt</span> <span class="o">%</span> <span class="p">(</span><span class="n">username_length</span><span class="p">,</span> <span class="s">'User'</span><span class="p">,</span>
<span class="s">'UID'</span><span class="p">,</span>
<span class="n">home_length</span><span class="p">,</span> <span class="s">'Home Dir'</span><span class="p">,</span>
<span class="s">'Description'</span><span class="p">)</span>
<span class="k">print</span> <span class="s">'-'</span> <span class="o">*</span> <span class="n">username_length</span><span class="p">,</span> <span class="s">'----'</span><span class="p">,</span> <span class="s">'-'</span> <span class="o">*</span> <span class="n">home_length</span><span class="p">,</span> <span class="s">'-'</span> <span class="o">*</span> <span class="mi">30</span>
<span class="c"># Print the data</span>
<span class="k">for</span> <span class="n">u</span> <span class="ow">in</span> <span class="n">interesting_users</span><span class="p">:</span>
<span class="k">print</span> <span class="n">fmt</span> <span class="o">%</span> <span class="p">(</span><span class="n">username_length</span><span class="p">,</span> <span class="n">u</span><span class="o">.</span><span class="n">pw_name</span><span class="p">,</span>
<span class="n">u</span><span class="o">.</span><span class="n">pw_uid</span><span class="p">,</span>
<span class="n">home_length</span><span class="p">,</span> <span class="n">u</span><span class="o">.</span><span class="n">pw_dir</span><span class="p">,</span>
<span class="n">u</span><span class="o">.</span><span class="n">pw_gecos</span><span class="p">)</span>
</pre></div>
</div>
<p>Most of the example code above deals with formatting the results
nicely. The <tt class="docutils literal"><span class="pre">for</span></tt> loop at the end shows how to access fields from
the records by name.</p>
<div class="highlight-python"><pre>$ python pwd_getpwall.py
User UID Home Dir Description
---------- ---- ----------------- ------------------------------
daemon 1 /var/root System Services
dhellmann 527 /Users/dhellmann Doug Hellmann
nobody 4294967294 /var/empty Unprivileged User
root 0 /var/root System Administrator</pre>
</div>
</div>
<div class="section" id="querying-user-by-name">
<h2>Querying User By Name<a class="headerlink" href="#querying-user-by-name" title="Permalink to this headline">¶</a></h2>
<p>If you need information about one user, it is not necessary to read
the entire password database. Using <tt class="docutils literal"><span class="pre">getpwnam()</span></tt>, you can retrieve
the information about a user by name.</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">pwd</span>
<span class="kn">import</span> <span class="nn">sys</span>
<span class="n">username</span> <span class="o">=</span> <span class="n">sys</span><span class="o">.</span><span class="n">argv</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span>
<span class="n">user_info</span> <span class="o">=</span> <span class="n">pwd</span><span class="o">.</span><span class="n">getpwnam</span><span class="p">(</span><span class="n">username</span><span class="p">)</span>
<span class="k">print</span> <span class="s">'Username:'</span><span class="p">,</span> <span class="n">user_info</span><span class="o">.</span><span class="n">pw_name</span>
<span class="k">print</span> <span class="s">'Password:'</span><span class="p">,</span> <span class="n">user_info</span><span class="o">.</span><span class="n">pw_passwd</span>
<span class="k">print</span> <span class="s">'Comment :'</span><span class="p">,</span> <span class="n">user_info</span><span class="o">.</span><span class="n">pw_gecos</span>
<span class="k">print</span> <span class="s">'UID/GID :'</span><span class="p">,</span> <span class="n">user_info</span><span class="o">.</span><span class="n">pw_uid</span><span class="p">,</span> <span class="s">'/'</span><span class="p">,</span> <span class="n">user_info</span><span class="o">.</span><span class="n">pw_gid</span>
<span class="k">print</span> <span class="s">'Home :'</span><span class="p">,</span> <span class="n">user_info</span><span class="o">.</span><span class="n">pw_dir</span>
<span class="k">print</span> <span class="s">'Shell :'</span><span class="p">,</span> <span class="n">user_info</span><span class="o">.</span><span class="n">pw_shell</span>
</pre></div>
</div>
<p>The passwords on my system are stored outside of the main user
database in a shadow file, so the password field, when set, is
reported as all <tt class="docutils literal"><span class="pre">*</span></tt>.</p>
<div class="highlight-python"><pre>$ python pwd_getpwnam.py dhellmann
Username: dhellmann
Password: ********
Comment : Doug Hellmann
UID/GID : 527 / 501
Home : /Users/dhellmann
Shell : /bin/bash
$ python pwd_getpwnam.py nobody
Username: nobody
Password: *
Comment : Unprivileged User
UID/GID : 4294967294 / 4294967294
Home : /var/empty
Shell : /usr/bin/false</pre>
</div>
</div>
<div class="section" id="querying-user-by-uid">
<h2>Querying User By UID<a class="headerlink" href="#querying-user-by-uid" title="Permalink to this headline">¶</a></h2>
<p>It is also possible to look up a user by their numerical user id.
This is useful to find the owner of a file:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">pwd</span>
<span class="kn">import</span> <span class="nn">os</span>
<span class="kn">import</span> <span class="nn">sys</span>
<span class="n">filename</span> <span class="o">=</span> <span class="s">'pwd_getpwuid_fileowner.py'</span>
<span class="n">stat_info</span> <span class="o">=</span> <span class="n">os</span><span class="o">.</span><span class="n">stat</span><span class="p">(</span><span class="n">filename</span><span class="p">)</span>
<span class="n">owner</span> <span class="o">=</span> <span class="n">pwd</span><span class="o">.</span><span class="n">getpwuid</span><span class="p">(</span><span class="n">stat_info</span><span class="o">.</span><span class="n">st_uid</span><span class="p">)</span><span class="o">.</span><span class="n">pw_name</span>
<span class="k">print</span> <span class="s">'</span><span class="si">%s</span><span class="s"> is owned by </span><span class="si">%s</span><span class="s"> (</span><span class="si">%s</span><span class="s">)'</span> <span class="o">%</span> <span class="p">(</span><span class="n">filename</span><span class="p">,</span> <span class="n">owner</span><span class="p">,</span> <span class="n">stat_info</span><span class="o">.</span><span class="n">st_uid</span><span class="p">)</span>
</pre></div>
</div>
<div class="highlight-python"><pre>$ python pwd_getpwuid_fileowner.py
pwd_getpwuid_fileowner.py is owned by dhellmann (527)</pre>
</div>
<p>The numeric user id is can also be used to find information about the
user currently running a process:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">import</span> <span class="nn">pwd</span>
<span class="kn">import</span> <span class="nn">os</span>
<span class="n">uid</span> <span class="o">=</span> <span class="n">os</span><span class="o">.</span><span class="n">getuid</span><span class="p">()</span>
<span class="n">user_info</span> <span class="o">=</span> <span class="n">pwd</span><span class="o">.</span><span class="n">getpwuid</span><span class="p">(</span><span class="n">uid</span><span class="p">)</span>
<span class="k">print</span> <span class="s">'Currently running with UID=</span><span class="si">%s</span><span class="s"> username=</span><span class="si">%s</span><span class="s">'</span> <span class="o">%</span> <span class="p">(</span><span class="n">uid</span><span class="p">,</span> <span class="n">user_info</span><span class="o">.</span><span class="n">pw_name</span><span class="p">)</span>
</pre></div>
</div>
<div class="highlight-python"><pre>$ python pwd_getpwuid_process.py
Currently running with UID=527 username=dhellmann</pre>
</div>
<div class="admonition-see-also admonition seealso">
<p class="first admonition-title">See also</p>
<dl class="last docutils">
<dt><a class="reference external" href="http://docs.python.org/library/pwd.html">pwd</a></dt>
<dd>The standard library documentation for this module.</dd>
<dt><tt class="xref py py-mod docutils literal"><span class="pre">spwd</span></tt></dt>
<dd>Secure password database access for systems using shadow passwords.</dd>
<dt><a class="reference internal" href="../grp/index.html#module-grp" title="grp: Unix Group Database"><tt class="xref py py-mod docutils literal"><span class="pre">grp</span></tt></a></dt>
<dd>The <a class="reference internal" href="../grp/index.html#module-grp" title="grp: Unix Group Database"><tt class="xref py py-mod docutils literal"><span class="pre">grp</span></tt></a> module reads Unix group information.</dd>
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