Cron jobs

Cron jobs are perfect for executing a specific task or script at a scheduled time or different time periods.

Cron jobs can be run hourly, daily, weekly and monthly.

Cron configuration file is located:

/etc/crontab

This file should look like this:

# Example of job definition:
# .---------------- minute (0 - 59)
# |  .------------- hour (0 - 23)
# |  |  .---------- day of month (1 - 31)
# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# |  |  |  |  |
# *  *  *  *  * user-name command to be executed

Execute a job every X minutes

*/5 * * * * /path/to/script/script.sh

Use */10 for every 10 minutes, */15 for every 15 minutes… and so forth..

Execute a job every X hours

0 */5 * * * /path/to/script/script.sh

Use */2 for every 2 hours, */3 for every 3 minutes… and so forth..

Execute a job every Xth day of the week

Lets assume you want to execute a cron job every Wednesday at midnight:

0 0 * * 3 /path/to/script/script.sh

or

0 0 * * Wed /path/to/script/script.sh

You can use the corresponding number or the three letters for each weekday:

0=Sun
1=Mon
2=Tue
3=Wed
4=Thu
5=Fri
6=Sat

Please note that numbers starts with 0 for Monday, and not 1.

Execute a job every X months

You need to specify the what specific month or months you want to job to be executed. Like January and September:

0 0 1 1,9 * /path/to/script/script.sh

or

0 0 1 Jan,Sep * /path/to/script/script.sh

If you only want January and September, you should use a comma. If you want the job to be executed starting January and ending September, you need to use this format: 1-9.

Video Thumbnail in Dolphin – Fedora 23/24

After a long, long, long time, finally I can view my videos thumbnails in Dolphin.

I reported a Bug in RPMFusion Bugzilla back in Januay 2016 and earlier this morning I got the surpise that it was Resolved!

I want to thank Leigh Scott for getting this done. I’m really happy about it, since I have lots and lots of videos and being able to look at a small thumbnail is really helpful.

So, to get the package installed, all you need to do is:

$sudo dnf install ffmpegthumbs

After that, just need to enable it in Dolphin by going to Preferences > Configure Dolphin > General > Previews > Video files (ffmpegthumbs) and that’s it!

Thanks again for making this happen.

Fix Video Thumbnails in Dolphin 15.08.1 (KDE 5.17.0) in Fedora 23

When updating KDE in my Fedora 23, I lost the video previews in Dolphin. Even after installing ffmpegthumbs did not work.

So here is the solution:

sudo cp /usr/share/kde4/services/ffmpegthumbs.desktop /usr/share/kservices5/
sudo cp /usr/lib64/kde4/ffmpegthumbs.so /usr/lib64/qt5/plugins/

You need to have installed ffmpegthumbs for this to work, to install it:

sudo dnf install ffmpegthumbs

And you need to enable the video preview again in Dolphin.

zsh with oh-my-zsh

Zsh is a shell designed for interactive use.

To install it in Fedora:

yum install zsh

Once installed, you can run it with:

zsh

This will create a new file: ~/.zshrc with all the defaults configurations.

oh-my-zsh

oh-my-zsh it’s a community-driven framework for managing your zsh configuration. Includes a bunch of plugins and themes.

To install it:

curl -L http://install.ohmyz.sh | bash

To set zsh as the default shell:

chsh -s /bin/zsh

And restart your terminal.

And for sharing or synchronizing history between Zsh and Bash:

$ cat ~/.histfile >> ~/.bash_history
$ youreditor ~/.zshrc
# Here change your config to:
HISTFILE=~/.bash_history
$ rm ~/.histfile

For themes and plugins for oh-my-zsh:

Themes: https://github.com/robbyrussell/oh-my-zsh/tree/master/themes
Plugins: https://github.com/robbyrussell/oh-my-zsh/tree/master/plugins

And that’s it.

Enjoy your zsh.

FUDCon Managua 2014

Well, FUDCon Managua is now over. It was awesome!!!

There were many interesting talks by Fedora Contributors and Users. I was able to be in a few of them and meet really interesting and kind people.

Some of the talks I attended were: oVirt, Nagios, Flask, Virtualization with KVM, OpenStack, SELinux, Icaro, among others.

Thanks to the people that gave time and energy into this, we really appreciate it.

I will be posting more information later, with URL to the talks when they are available online.

Now, some pictures I was able to take during the event.

DSC04151

DSC04161

DSC04165

DSC04177

DSC04246

DSC04247

DSC04255

Asus G74SX-DH71 Keyboard lights Function Keys in KDE (Debian and Fedora)

I was trying for a while to make my Function Keys (volume, keyboard lights, etc) work in KDE 4.x, and I was finely able to do it with a *funny* workaround. It turns out that the Fn keys works just fine in Gnome, so I dig a little bit and found that the responsible of making this work is a small daemon called gnome-settings-daemon… So it’s just a matter of starting up this daemon in KDE and that’s it.

So, for doing that I just needed to add the next bash file:

$vi ~/.kde/Autostart/gnome-settings-daemon.sh

and add this line:

For Debian:

gnome-settings-daemon

For Fedora:

/usr/libexec/gnome-settings-daemon

we save the file and then add exec permissions

$chmod u+x ~/.kde/Autostart/gnome-settings-daemon.sh

Now you need to logout and login again and that’s it.

For getting the screen brightness function keys working properly, we need to edit our xorg.conf file:

#vi /etc/X11/xorg.conf

Under the section “Device” we need to add:

Option "RegistryDwords" "EnableBrightnessControl=1"

So, at the end, our “Device” section should look similar to:

Section "Device"                                                                                                                     
    Identifier  "Video Card"                                                                                                         
    Driver      "nvidia"                                                                                                             
    Option "RegistryDwords" "EnableBrightnessControl=1"                                                                              
EndSection

You need to reboot in order to get this working.

Hope that works for you. 🙂

Fedora 16 brightness issue in Acer Aspire 4750

I recently bought an Acer Aspire 4750, it’s a cool laptop, the only thing I regret it’s the screen resolution, I’m used to a Full HD Monitor, since I have one at work and in my desktop (still use it)… but, this is not about that.. it’s about a brightness issue in my laptop, since I can’t use the FN key + left and right arrow to lower or upper the brightness out of the box in Fedora 16.

This is the solution:

Edit /etc/grub2.cfg (you obviously need to be root to do so) and at the line that starts with “linux /vmlinuz-…” add this at the end:

"acpi_backlight=vendor acpi_osi=linux" (without the quotes, of course)

If you don’t know how to do this:

vi /boot/grub/grub.conf

So for example your first Fedora block should become:

menuentry 'Fedora (3.2.6-3.fc16.x86_64)' --class fedora --class gnu-linux --class gnu --class os {
	load_video
	set gfxpayload=keep
	insmod gzio
	insmod part_msdos
	insmod ext2
	set root='(hd0,msdos2)'
	search --no-floppy --fs-uuid --set=root 8172b21b-d5f0-44b2-a899-d6c5d91d9311
	echo 'Loading Fedora (3.2.6-3.fc16.x86_64)'
	linux	/vmlinuz-3.2.6-3.fc16.x86_64 root=/dev/mapper/vg_wportalaptop-lv_root ro rd.md=0 rd.dm=0 rd.lvm.lv=vg_wportalaptop/lv_swap rd.lvm.lv=vg_wportalaptop/lv_root quiet SYSFONT=latarcyrheb-sun16 rhgb rd.luks=0 LANG=es_ES.UTF-8  KEYTABLE=es acpi_backlight=vendor acpi_osi=linux
	echo 'Loading initial ramdisk ...'
	initrd /initramfs-3.2.6-3.fc16.x86_64.img
}

You may want to try this with the first block in your grub2.conf, so if something goes wrong you can always boot with an old kernel and fix it.

Hope it works for you..

Enjoy..