lfs-book-zh_CN/chapter06/create-utmp.xml

<sect2>
<title>Creating the /var/run/utmp, /var/log/wtmp and /var/log/btmp files</title>

<para>Programs like login, shutdown, uptime and others want to read from and 
write to the /var/run/utmp, /var/log/btmp and /var/log/wtmp. These files contain 
information about who is currently logged in. They also contain information 
on when the computer was last booted and shutdown and a record of the
bad login attempts.</para>

<para>Create these files with their proper permissions by running the
following commands:</para>

<para><screen><userinput>touch /var/run/utmp /var/log/{btmp,lastlog,wtmp} &amp;&amp;
chmod 644 /var/run/utmp /var/log/{btmp,lastlog,wtmp}</userinput></screen></para>

</sect2>