I want to reboot my raspberry pi every day at 4 in the morning because it's the perfect time to reboot because its guaranteed no one will connect to it, As I am hosting a local server on there and just to ensure that it doesn't slow down or anything I want to reboot it.
I heard you can use crontab?
Would it look like this?
0 0, 4 * * * reboot ?
Or is this 4 at night?
I don't understand how PM or AM works in this format or system.
Cron uses the 24 hour clock. PM is hours between 12 and 23.
4am every day would be:
0 4 * * * reboot
(without the extra 0, you've inserted in yours).
This line will reboot it #4 am in the morning
0 4 * * * reboot
I prefer using https://crontab.guru/#00_00__ this will help you time your cron events.
This is an excellent page to verify your cron time.
In a Linux CentOS 5 machine, I am running process.sh using a cronjob at #reboot, every day (the machine gets shut off every night and turned on every morning).
process.sh takes the 'date' of the computer, and writes it to a log file, then exits.
When I check the logfile, the timestamp in it says "Tue Jan 1 13:14:38 GMT 2008"
When I go to the console of the computer and give it the 'date' command, it prints the correct date.
My best guess is that my cronjob is running BEFORE the computer sets its correct time.
Is there a way to fix this?
The battery that powers the CMOS memory on your motherboard may have run out. Try replacing it by a fresh one. It should look something like this.
This advice is based on the fact that the date of your log entry is "Jan 1 2008" which looks conspicuously like an epoch your motherboard may use. However, the time-of-day 13:14:38 is a little off for this; while the 13 hour shift can be explained if you are in the correct time zone, the nearly 15 minute offset seems odd. Unless your computer takes that long to boot to the point where cron executes your job. And of course, the reason why you eventually see the correct time is probably that ntp fixed the system time, as others have noted.
I'm building an arcade cabinet and would like to have random games launch after 15 minutes of inactivity. I'm not sure how to determine the time since the last user input. This is a pretty standard screensaver with xserver, however I can't seem to find a way to do it without x running.
Specifically I'm running RetroPie on a Raspberry Pi 2. X is installed but not running. The front end is emulationstation.
Any help would be appreciated, thanks.
i want to write a script in debian , which will make an application stop at a certain system time . Before anyone thinks its a homework , it is not . My internet connection allows unlimited download only in a certain time period , so i would like to stop the torrent application once the time period is over with .
Cron (http://en.wikipedia.org/wiki/Cron) should be your friend here. Add 2 cron jobs to your crontab, one to start the script and one to stop it.
Check into crontab -e - you want something like this in there:
0 2 * * * /path/to/yourtorrentclient start
0 6 * * * /path/to/yourtorrentclient stop
if you want to turn it on at 02:00 every day, and turn it off at 06:00 every day, and assuming yourtorrentclient responds to arguments start and stop. Rewrite as needed.
How can I get a history of uptimes for my debian box? After a reboot, I dont see an option for the uptime command to print a history of uptimes. If it matters, I would like to use these uptimes for graphing a page in php to show my webservers uptime lengths between boots.
Update:
Not sure if it is based on a length of time or if last gets reset on reboot but I only get the most recent boot timestamp with the last command. last -x also does not return any further info. Sounds like a script is my best bet.
Update:
Uptimed is the information I am looking for, not sure how to grep that info in code. Managing my own script for a db sounds like the best fit for an application.
Install uptimed. It does exactly what you want.
Edit:
You can apparantly include it in a PHP page as easily as this:
<? system("/usr/local/bin/uprecords -a -B"); ?>
Examples
the last command will give you the reboot times of the system. You could take the difference between each successive reboot and that should give the uptime of the machine.
update
1800 INFORMATION answer is a better solution.
You could create a simple script which runs uptime and dumps it to a file.
uptime >> uptime.log
Then set up a cron job for it.
Try this out:
last | grep reboot
according to last manual page:
The pseudo user reboot logs in each time the system is rebooted.
Thus last reboot will show a log of all reboots since the log file
was created.
so last column of #last reboot command gives you uptime history:
#last reboot
reboot system boot **************** Sat Sep 21 03:31 - 08:27 (1+04:56)
reboot system boot **************** Wed Aug 7 07:08 - 08:27 (46+01:19)
This isn't stored between boots, but The Uptimes Project is a third-party option to track it, with software for a range of platforms.
Another tool available on Debian is uptimed which tracks uptimes between boots.
I would create a cron job to run at the required resolution (say 10 minutes) by entering the following [on one single line - I've just separated it for formatting purposes] in your crontab (cron -l to list, cron -e to edit).
0,10,20,30,40,50 * * * *
/bin/echo $(/bin/date +\%Y-\%m-\%d) $(/usr/bin/uptime)
>>/tmp/uptime.hist 2>&1
This appends the date, time and uptime to the uptime.hist file every ten minutes while the machine is running. You can then examine this file manually to figure out the information or write a script to process it as you see fit.
Whenever the uptime reduces, there's been a reboot since the previous record. When there are large gaps between lines (i.e., more than the expected ten minutes), the machine's been down during that time.
This information is not normally saved. However, you can sign up for an online service that will do this for you. You just install a client that will send your uptime to the server every 5 minutes and the site will present you with a graph of your uptimes:
http://uptimes-project.org/
i dont think this information is saved between reboots.
if shutting down properly you could run a command on shutdown that saves the uptime, that way you could read it back after booting back up.
Or you can use tuptime https://sourceforge.net/projects/tuptime/ for a total uptime time.
You can use tuptime, a simple command for report the total uptime in linux keeping it betwwen reboots.
http://sourceforge.net/projects/tuptime/
Since I haven't found an answer here that would help retroactively, maybe this will help someone.
kern.log (depending on your distribution) should log a timestamp.
It will be something like:
2019-01-28T06:25:25.459477+00:00 someserver kernel: [44114473.614361] somemessage
"44114473.614361" represents seconds since last boot, from that you can calculate the uptime without having to install anything.
Nagios can make even very beautiful diagrams about this.
Use Syslog
For anyone coming here searching for their past uptime.
The solution of #1800_Information is a good advise for the future, but I needed to find information for my past uptimes on a specific date.
Therefore I used syslog to determine when that day the system was started (first log entry of that day) and when the system was shutdown again.
Boot time
To get the system start time grep for the month and day and show only the first lines:
sudo grep "May 28" /var/log/syslog* | head
Shutdown time
To get the system shutdown time grep for the month and day and show only the last few lines:
sudo grep "May 28" /var/log/syslog* | tail