Gladly this is just another global shortcut like any other ones (alt-F1 for menu, for example), therefore it can be disabled the same way: System menu » Preferences » Keyboard Shortcuts, in the window you can find under Desktop » Log out. Click on it, and disable it with a backspace.

Successfully got rid of an annoyance – “great success!” as my colleague said :)

now=`date +%s`
mtime=`stat -c %Z /some/file`
if [ $((now - mtime)) -gt 3600 ]; then
    echo "xy seems to be out-of-date."
fi

This checks the current time and the modification time of the file, calculates the difference and checks if that’s greater than 3600 seconds (1 hour), then echoes something if it is greater.

This can be written in a more simplest way:

[ $((`date +%s` - `stat -c %Z /some/file`)) -gt 3600 ] && \
    echo "xy seems to be out-of-date."

This way you can easily put it in cron, like this, so it is checked twice a day:

0 9,21 * * * user [ $((`date +\%s` - `stat -c \%Z /some/file`)) -gt 3600 ] && \
    echo "xy seems to be out-of-date."

You can remove the “\” at the end of the lines and write the commands in one line. BUT the “\”s before the “%” have to be there to maintain proper escaping! ]]> http://random.kakaopor.hu/getting-file-age-in-a-simple-way/feed 0 http://random.kakaopor.hu/getting-file-age-in-a-simple-way http://feedproxy.google.com/~r/kakaopor/random/~3/2rqvhMAuQ_I/lunar-date-function-for-php-time-on-the-moon-lst http://random.kakaopor.hu/lunar-date-function-for-php-time-on-the-moon-lst#comments Mon, 28 Feb 2011 23:35:39 +0000 kakaopor http://random.kakaopor.hu/?p=195 What is the time on the Moon?

A few guys leading a project called LunarClock.org designed a Lunar date and time system, the Lunar Standard Time (LST).

It is a really simple method of the time tracking on the Moon (theoretically of course, as no one lives there – yet ;)). It based on the good old scheme of the “Earth time”: it has seconds, minutes, hours, cycles, days and years. The only unfamiliar thing is the cycles thing between the hours and days (and the lack of the months). It is necessary in case we stick to the definition of the day: the time between two noons. On the moon it is a really long period, it lasts for about 29.53 days on Earth! It would be a bit strange to say “it is half past 143″, so they introduced the cycles. And because the days are so long, 365.25 (or so) of them would be… a lot of days on Earth, therefore the months are dismissed and the Lunar years are simply 12 Lunar days long – about 354.36 Earth days. This is so close to our 365.25 days per year!

Another interesting thing is the days on Moon have names just as our months. They named the twelve days after the twelve men who walked on the Moon during the Apollo missions. I think this is a nice idea.

Well okay, enough of the chit-chat, here is a demo of the PHP class I mentioned in the title:

The current time on the Moon is 44-09-11 ∇ 14:06:54, Young.

So this is the current time on the Moon, so far from here, so great differences between the days, but still very familiar.

Great job guys from LunarClock.org, I like LST!

You can download the PHP function (which can be used almost exactly as the original date() function) from here: http://dev.kakaopor.hu/stuffs/lunar_date.php.txt (can be freely used/redistributed/modified/etc. of course)

For more about the LST, Lunar Standard Time, see: http://lunarclock.org/

The solution for this is an SSH escape sequence, the sequence of the enter, tilde and period keys (so you should press enter and then “~” followed by “.”). This forces the SSH connection to close so your client should exit.

Source: Way to avoid ssh connection timeout & freezing of terminal tab question on superuser.com.

My disks and motherboard AFAIK were not hot-swap-compatible, but with some SCSI/SATA commands I was able to have a behavior very similar to that.

The first part of hot-swapping of course is the hardware – I used mobile racks for this purpose (something like this, but with a separate power switch), but you can simply unplug/plug your disks as well in case you are brave enough to do so. I think the mobile rack is far more safe (I have seen dead hard drives because of an improperly connected power connector).

The magic behind the hot-swapping is basically two SCSI commands: remove-single-device and add-single-device. With these you are able to tell the SCSI driver to release and to grab the disks again.

Be sure to unmount and to have the drive absolutely unused when you tell the driver to release the devices – it will not check if the drives are in use or not and your kernel may get confused about the disappearing drives. (Believe me, I tried :)

One more thing you need to know before using those commands: the host, channel, ID, LUN numbers of your drives. You can find these numbers easily, simply cat /proc/scsi/scsi, or ls /dev/disks/by-path/*.

Okay, enough of chattering, here is the Bash script (assuming you have a proper fstab entry for /mnt/swaptest, and the SCSI id of 0:0:1:0):


# unmount the file system
umount /mnt/swaptest || exit 1

echo "Swap was succesful."


Basically that’s all.

You might use mdadm to have a RAID-1 array, and have a copy of your system in a safe place, you can handle this easily as well:

# mark the disk as faulty for further remove from the array
mdadm /dev/md0 --fail /dev/sdb1

echo "Swap was succesful."


Of course these swaps can become more complex, using more disks, more RAID arrays, LVM volumes, but these are the basics – I assume you can figure out the rest :)

Oh, and the disclaimer: always have a backup of your data before trying these steps/commands, and I have read not all the drives are capable of doing such things, I personally do not think this can lead to hardware failure but I cannot be certain about it. Please try anything at your own risk.

This had been happening in console and under X too. I thought it might be a kernel-related issue, some kind of a timer or interrupt problem, maybe timeout.

All in all this turned out to be an APIC problem, and the machine is working perfectly with a noapic boot parameter.

This is the few lines of default initramfs script which is responsible for the behaviour described above:

/usr/share/initramfs-tools/scripts/local-top, from line 40:

# Make sure that we have a d-m path
vg=${vg#/dev/mapper/}
if [ "$vg" = "$1" ]; then
    return 1
fi


And it wouldn’t be enough to remove this check, because there is an another one for the format:

# Make sure that the device includes at least one dash
if [ "$(echo -n "$vg" | tr -d -)" = "$vg" ]; then
    return 1
fi


So you have to use the /dev/mapper/[vg_name]-[lv_name] format in GRUB’s menu.lst (or LILO’s lilo.conf) to boot from an LVM device. Unless you change the script above, of course :)

Source: https://code.ticketmaster.com/trac/browser/spine/trunk/lib/Spine/Plugin/SystemInfo.pm?rev=123#L225

ORA-19502: write error on file "/path/to/datafile.dbf", blockno 1669073 (blocksize=8192)
ORA-27072: File I/O error
Linux Error: 2: No such file or directory


ORA-19502: write error on file "/path/to/datafile.dbf", blockno 1831475 (blocksize=8192)
ORA-27072: File I/O error
Linux Error: 13: Permission denied


Long story short, these messages are exotic forms of the boring “Out of disk space” message.

And even if you have enough space for the restore, you may need ~+20% spare space. Don’t know exactly why, but that was needed in my case.

Oracle loves disk space and strange messages – lesson learned.

http://dev.kakaopor.hu/stuffs/bootsplash-3.1.6a-2.6.32.diff