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| <h3 class="section">29.12 The User Accounting Database</h3> |
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| <p><a name="index-user-accounting-database-3336"></a> |
| Most Unix-like operating systems keep track of logged in users by |
| maintaining a user accounting database. This user accounting database |
| stores for each terminal, who has logged on, at what time, the process |
| ID of the user's login shell, etc., etc., but also stores information |
| about the run level of the system, the time of the last system reboot, |
| and possibly more. |
| |
| <p>The user accounting database typically lives in <samp><span class="file">/etc/utmp</span></samp>, |
| <samp><span class="file">/var/adm/utmp</span></samp> or <samp><span class="file">/var/run/utmp</span></samp>. However, these files |
| should <strong>never</strong> be accessed directly. For reading information |
| from and writing information to the user accounting database, the |
| functions described in this section should be used. |
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| <ul class="menu"> |
| <li><a accesskey="1" href="Manipulating-the-Database.html#Manipulating-the-Database">Manipulating the Database</a>: Scanning and modifying the user |
| accounting database. |
| <li><a accesskey="2" href="XPG-Functions.html#XPG-Functions">XPG Functions</a>: A standardized way for doing the same thing. |
| <li><a accesskey="3" href="Logging-In-and-Out.html#Logging-In-and-Out">Logging In and Out</a>: Functions from BSD that modify the user |
| accounting database. |
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