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6
votes
3answers
4k views

What could cause a cron to run twice at the same moment?

I have a cron that is setup to run every Monday at 1 AM 0 1 * * 1 /script/dir/script >> /script/dir/file.log After two years of running as expected, it ran twice on June 18, with the second ...
1
vote
1answer
18 views

rtcwake not working on Ubuntu 14.04 installed on MacBook Air (mid 2012)

I have installed Ubuntu 14.04 GNU/Linux on a MacBook Air (mid 2012). I'm trying to use rtcwake to implement a "delayed hibernation from suspend", as in https://askubuntu.com/a/33192 (the particular ...
0
votes
1answer
15 views

Is clock_getres the proper function for obtaining the resolution for Ubuntu 16.04 clock_gettime()?

Is clock_getres the proper function for obtaining the resolution for Ubuntu 16.04 clock_gettime()? If it is , how do I use the result to do this calculation? 64 bit integer has 15 base 10 digits of ...
3
votes
1answer
27 views

PC with short-lived RTC battery - how to immediately time-sync on boot and avoid time jumps

I've got a 64-bit Intel PC running Debian 8 with a capacitor-based clock, which means after 3 days without power the time is lost from the hardware clock. To help work-around this, I was thinking we ...
2
votes
1answer
75 views

Switch off 11-minute kernel mode

If ntpd works, then the kernel copies system time to hardware clock every 11 minutes. It is shown by command adjtimex --print I want to stop the kernel eleven mode. If I run hwclock --...
3
votes
1answer
50 views

UNIX Seconds, TAI (SI) Seconds, Leap Seconds, and Real-World Code

I've read a lot about UNIX Time lately, most of it incoherent, much of it contradictory. I am trying to reconcile conversions between UNIX Time (hereafter, for simplicity, UXT), TAI, and UTC, and to ...
0
votes
1answer
40 views

Linux Voyager Desktop clock bug

Hello everyone , as you can see I have a problem with the desktop clock , I tried switching main language and it didn't work . I couldn't find any other forums with the same problem either . I am not ...
0
votes
0answers
49 views

RedHat:how to make system read /etc/sysconfig/clock settings without restarting system

In legacy red hat enterprise linux system which do not provide hwclock, I am changing UTC value in /etc/sysconfig/clock and when I check in /etc/adjtime this value is not reflected with expected value....
16
votes
2answers
736 views

Does crond handles summer time +1 hour change?

Last weekend we had to change the time from 02:00 to 03:00. Question: What would happen if there was a cronjob at 02:30? crond is a very old solution for scheduling, it should probably handle it, ...
26
votes
4answers
155k views

Linux: set date through command line

How to change the system date in Linux ? I want to change: Only Year Only Month Only Date Any combination of above three
3
votes
1answer
75 views

How to set time in nanoseconds?

I have a Raspberry Pi with a GPS module connected to it. Since all GPS satellites have very precise atomic clocks on them, I would like to synchronize the Pi's clock to the satellites' clocks. I know ...
0
votes
1answer
93 views

Time sync in VM between Windows as host and CentOS as guest without network

A question concerning the time synchronization between the host and the guest System. I am using Windows 7 as my host OS and CentOS 7 is installed as VM in an Oracle VirtualBox environment without ...
12
votes
4answers
8k views

How can I measure and prevent clock drift?

On several production platforms we have observed symptoms which appear to suggest that the time of day clock is periodically jumping forward or backward. The jumps are typically around 1 second, ...
2
votes
0answers
44 views

How do I adjust the format of GNOME's digital clock to an advanced custom format?

The digital clock of GNOME I am referring to is indicated in this screenshot: This is the advanced custom format I would like GNOME's digital clock to have: %l:%M:%S %p %A, %e %B %Y at the moment ...
1
vote
2answers
361 views

Cannot access the hardware clock as a non-root user

I try to use the hwclock but I get this output: [arkadi@arkadi-linux /home/arkadi $]hwclock hwclock: Cannot access the Hardware Clock via any known method. hwclock: Use the --debug option to see the ...
4
votes
2answers
450 views

RTC time synchronization not working (CONFIG_RTC_SYSTOHC)

I have the option CONFIG_RTC_SYSTOHC enabled in my kernel: Device Drivers ---> [*] Real Time Clock ---> [*] Set the RTC time based on NTP synchronization The help says: ...
2
votes
1answer
30 views

Clocks, Hardware, and Booting

A few days ago, I was having some difficulty booting my Mint 17.2 installation. Essentially, after boot my screen would go black, and I would not be able to do anything - even after some time, the GUI ...
0
votes
1answer
121 views

How to set the clock in Debian 8

I though I was reasonably versed in low level maintenance, but apparently not. Help! I'll spare you the sorry details, but my questions are: What command do you use in Debian 8 instead of hwclock, ...
0
votes
1answer
177 views

bash + timer in dialog window

Is it possible to insert the following code ( a timer ) in the dialog progress bar ? date1=`date +%s`; while true; do echo -ne "$(date -u --date @$((`date +%s` - $date1)) +%H:%M:%S)\r"; ...
1
vote
1answer
1k views

How to have time synchronization work on localtime?

The Arch wiki suggests Time standard Recommended: Set both Arch Linux and Windows to use UTC, following Time#UTC in Windows. Also, be sure to prevent Windows from synchronizing the time ...
5
votes
2answers
814 views

FreeBSD and Windows show different times

In a dual-boot system, I usually use FreeBSD 9 but when I boot to Windows 7 my system time in both OS automatically change and show incorrect time. What's the problem and How can I solve it?
3
votes
1answer
160 views

Automatically synchronization between system time and hardware clock time

I'm working with a Linux embedded board. It uses Linux kernel v2.6.37 with an external I2C RTC cbc34803. I've successfully intergrated the RTC hardware. It works correctly except the problem ...
2
votes
1answer
840 views

RTC clock time sync with the Linux time on Startup

The RTC remembers its time set, and how does the linux kernel gets this time from dev/rtc and set it as the linux time. In other words on boot up - when does kernel reads the rtc and updates its linux ...
10
votes
7answers
19k views

How do I set time and date from the Internet?

How do I retrieve the date from the Internet and set my computer's clock, from the command line?
2
votes
1answer
129 views

Is it possible to read PVclock from user space?

Is it possible to read clocksource xen or kvmclock using some user space tool? Referring to /sys/devices/system/clocksource/clocksource0/current_clocksource. Reading the actual value of the pvclock. ...
1
vote
1answer
446 views

Clock drift in a VirtualBox guest

I've done this command this morning: root@xxx:01:21:17:/home/xxx$ date --set "2015-08-06 02:54" Thu Aug 6 02:54:00 WIB 2015 root@xxx:02:54:00:/home/xxx$ hwclock --set --date="2015-08-06 02:54" ...
1
vote
2answers
298 views

Synchronize the date and time on compute nodes

I want to set a job on compute nodes but I checked and see time and date of compute nodes are not sync with the head nodes. Head node shows: Wed Jul 22 16:57:32 PDT 2015 node 2 shows: Wed Jul 22 11:...
4
votes
2answers
566 views

Mysterious “unable to resolve host” in dead.letter

In the ~ directory of the root user on my debian wheezy server regularly appears file named dead.letter with (currently) the following content: orion : Jul 25 10:17:31 : root : unable to resolve host ...
1
vote
1answer
122 views

How to get a UTC clock widget on Awesome WM?

Is there a way to get a second clock widget in Awesome WM displaying UTC datetime, without having to change my timezone?
1
vote
2answers
83 views

Get Real BiosTime using CentOS 6.x and make permanentely SystemTime = BiosTime [closed]

My first SO is Windows 7, and it is synchronized with Bios Time... Later I installed CentOS, but... I want to have synchronized my CentOS with Windows and Time Bios! I was checking time (before ...
4
votes
6answers
877 views

How to know during system start when system time becomes correct from NTP

I have a Raspberry Pi running Raspbian (Debian derivative) that is recording real-time temperatures. As part of this, I need a clock that is accurate to within a few seconds. In normal operation when ...
5
votes
5answers
5k views

How to get system time with microsecond Resolution

I want to know current system time with microsecond Resolution. date +%s returns Time in seconds since epoch(1-1-1970). How can I get time in microseconds Resolution. How much delay is in querying ...
1
vote
1answer
253 views

Is it possible to speed up my Linux Clock?

Is it possible to modify the Unix Time Clock so that the clock is running ten times faster? Something like a fast-forward by increasing a clock frequency or change the clock tick time? Background is ...
1
vote
1answer
100 views

How do I keep the time on a server (virtual machine) updated over time?

I have a virtual machine running headless in my machine. When I start it for the first time, the result of date command is correct. But after about a day or 2, I SSH into it and the date command has ...
1
vote
0answers
65 views

How can I consistently tell OpenSUSE to refresh the clock / current time?

I use OpenSUSE in a VM and sometimes want to save the machine and get back to work later. I haven't had much success with hibernate or suspend, so I simply save the state of the machine and resume ...
-1
votes
1answer
47 views

separate the system & hardware clock in linux

I want to separate the system clock from the hardware clock which I synchronize first. But now I want to change both: hardware clock with the UTC time & system with the GPS time.
2
votes
0answers
250 views

KDE5 Digital clock widget show a different time, than the configured [closed]

I'm using KDE 5 over Arch Linux, and the digital clock widget show a different time than the configured for kde. The widget can be configured to show a different time changing the timezone for it. But ...
3
votes
1answer
1k views

Automatically update hwclock at boot

We're having a small issue with our Beagle Bone Blacks. Since they do not come with a RTC battery, when they lose power, the hardware clock gets messed up. I need a simple and clean way of syncing the ...
0
votes
1answer
130 views

script does not execute

I have rPi B+ running ArchLinux with kernel Linux comp001 3.18.6-2-ARCH #1 PREEMPT Sun Feb 8 09:43:43 MST 2015 armv6l GNU/Linux with Real Time Clock hardware RTC Pi. However, I would like to check if ...
1
vote
3answers
5k views

how to disable time sync in VM guest?

I have a desktop (centos 6) that has a VM guest (RedHat 5.5). I just try to set the date to past time in VM guest. And it works. However, after 50 minutes, the time is sync to current time. After I ...
0
votes
1answer
237 views

FreeBSD 9.3 date shows UTC when rc.conf and PostgreSQL show “America/Los_Angeles”

We're testing FreeBSD 9.3, where I had the system configured to use America/Los_Angeles as the timezone, and we've got the ntp server pointed at pool.ntp.org. Everything was fine, until I noticed ...
1
vote
0answers
233 views

How do I remove the clock?

In messing around with trying to add an analog clock to the panel, I inadvertently added a second clock. when I right click the panel applet, there is no option to remove the 2nd clock applet. So, ...
2
votes
1answer
257 views

Why does the clock need a shared memory segment?

This is a combination of programming and Linux question but I think it suits better here. I am writing an application that works with ipcs (shared memory segments) and after each running I am ...
0
votes
1answer
265 views

Changing linux config from 32 bit to 64 bit loses RTC

I have a config from a 32-bit linux 3.12.18, and was trying to compile a 64 bit version with most settings like selected drivers etc. the same as in 32 bit version. For this I used make menuconfig ...
3
votes
2answers
508 views

What does the change of the clocksource influence?

The output of cat /sys/devices/system/clocksource/clocksource0/available_clocksource lists the available hardware clocks. I have changed the clocks, without any visible difference. sudo /bin/sh -c '...
2
votes
1answer
2k views

How to move system clock time forward/backward?

I know commands for setting specific time and/or date, but can't find ones which move the time relative to the current time. What are the commands to move the time forward/backward x seconds/minutes/...
3
votes
1answer
589 views

system clock is off by one hour after every reboot

Every time I start my laptop, the clock is off by exactly one hour. I have to run ntpdate to fix it. Next time I restart the laptop, it will be off again. I have timezone set up correctly. I am ...
1
vote
0answers
927 views

RTC is not saving time after hwclock

So I'm having quite a bit of trouble trying to get my system to set the hardware clock's time. Here is what I did just now, everything has worked, right? The first and last command seem to indicate ...
3
votes
1answer
843 views

How to make awesomewm textclock reflect timezone change?

I am using the awful.widget.textclock widget to display the time in Awesome WM on Arch Linux, and I am using a program called tzupdate to automatically update my system time according to geolocation ...
4
votes
4answers
2k views

Clock skews on remote machines

I am performing some experiments on a network of about 10 remote Linux computers which are geographically scattered. I suspect some of them have clock skews but they are seen transiently (eg. once in ...