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Diffstat (limited to 'chapter07/setclock.xml')
| -rw-r--r-- | chapter07/setclock.xml | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/chapter07/setclock.xml b/chapter07/setclock.xml index d933eb59f..0527fac00 100644 --- a/chapter07/setclock.xml +++ b/chapter07/setclock.xml @@ -7,6 +7,36 @@ <title>Configuring the setclock Script</title> <?dbhtml filename="setclock.html"?> +<indexterm zone="ch-scripts-setclock"> +<primary sortas="d-setclock">setclock</primary> +<secondary>configuring</secondary></indexterm> + +<para>The <command>setclock</command> script reads the time from the hardware clock, +also known as BIOS or the Complementary Metal Oxide Semiconductor +(CMOS) clock. If the hardware clock is set to UTC, this script will convert the hardware clock's time to +the local time using the <filename>/etc/localtime</filename> file +(which tells the <command>hwclock</command> program which timezone the +user is in). There is no way to +detect whether or not the hardware clock is set to UTC time, so this +needs to be manually configured.</para> + +<para>If you cannot remember whether or not the hardware +clock is set to UTC time, find out by running +the <userinput>hwclock --localtime --show</userinput> command. This will tell +what the current time is according to the hardware clock. If this time +matches whatever your watch says, then the hardware clock is set to +local time. If the output from <command>hwclock</command> is not local +time, chances are it is set to UTC time. Verify this by adding or +subtracting the proper amount of hours for the timezone to this +<command>hwclock</command> time. For example, if you live in the MST +timezone, which is also known as GMT -0700, add seven hours to the local +time. Then, account for Daylight Savings Time, which requires +subtracting an hour (or only add six in the first place) during the summer +months.</para> + +<para>Change the value of the <envar>UTC</envar> variable below +to a value of <parameter>0</parameter> (zero) if the hardware clock +is <emphasis>not</emphasis> set to UTC time.</para> <para>Create a new file <filename>/etc/sysconfig/clock</filename> by running the following:</para> @@ -19,4 +49,9 @@ UTC=1 # End /etc/sysconfig/clock</literal> EOF</userinput></screen> +<para>A good hint explaining how to deal with time on LFS is available +at <ulink url="&hints-root;time.txt"/>. It explains issues such as +time zones, UTC, and the <envar>TZ</envar> environment variable.</para> + </sect1> + |