Moxa UC-8416-T-LX [26/90] Etc resolv conf file hwclock w sleep 100 updates every 100 seconds the min time is 100 seconds change 100 to a larger number to update rtc less often

Moxa UC-8481-LX [26/90] Etc resolv conf file hwclock w sleep 100 updates every 100 seconds the min time is 100 seconds change 100 to a larger number to update rtc less often
UC-8410/8416/8418/8430 Managing Embedded Linux
3-10
# /etc/resolv.conf file.
hwclock –w
sleep 100 # Updates every 100 seconds. The min. time is 100 seconds. Change 100
to a larger number to update RTC less often.
Save the shell script using any file name. E.g., fixtime
How to run the shell script automatically when the kernel boots up
Copy the example shell script fixtime to directory /etc/init.d, and then use
chmod 755 fixtime to change the shell script mode. Next, use vi editor to edit the file /etc/inittab. Add the
following line to the bottom of the file:
ntp : 2345 : respawn : /etc/init.d/fixtime
Use the command #init q to re-init the kernel.
CronDaemon to Execute Scheduled
Commands
Start Cron from the directory /etc/rc.d/rc.local. It will return immediately, so you do not need to start it with
an ampersand (&) to run in the background.
The Cron daemon will search /etc/cron.d/crontab for crontab files, which are named after accounts in
/etc/passwd.
Cron wakes up every minute, and checks each command to see if it should be run in the current minute.
Modify the file /etc/cron.d/crontab to set up your scheduled applications. Crontab files have the following
format:
mm h dom mon dow user command
min hour date month week user command
0-59 0-23 1-31 1-12 0-6 (0 is Sunday)
The following example demonstrates how to use Cron.
The following steps show how to use cron to update the system time and RTC time every day at 8:00.
STEP1: Write a shell script named fixtime.sh and save it to /home/.
#!/bin/sh
ntpdate time.nist.gov
hwclock –w
exit 0
STEP2: Change mode of fixtime.sh
#chmod 755 fixtime.sh
STEP3: Modify /etc/cron.d/crontab file to run fixtime.sh at 8:00 every day.
Add the following line to the end of crontab:
* 8 * * * root /home/fixtime.sh
STEP4: Enable the cron daemon manually.
#/etc/init.d/cron start
STEP5: Enable cron when the system boots up.
Add the following line in the file /etc/init.d/rc.local
#/etc/init.d/cron start

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