sys-unconfig command to reconfigure your system from next boot..

sys-unconfig is a shell script to reconfigure the system upon next boot .. The man page description is more than enough to know what parameters are reconfigured from next boot..

sys-unconfig provides a simple method of reconfiguring a system in a new environment. Upon executing sys-unconfig will halt your system,
and run the following configuration programs at boot: passwd (to change the root password), netconfig, timeconfig, kbdconfig, authconfig,
and ntsysv.

A file ( hidden) called “unconfigured” will be present inside “/” when you run sys-unconfig command . The presence of this file will cause /etc/rc.d/rc.sysinit to run the programs mentioned above.

Please note that, running “sys-unconfig” command will cause the system to go down immediately..

Also, all persistent rules will be deleted from /etc/udev/rules.d/.

Fedora 20 beta release (Heisenbug) announcement and 10th year of selinux!

I would like to share this news with you guys..

The Fedora Project announced the beta release of Fedora 20, code-named “Heisenbug.” A community-produced, free, Linux-based operating system, Fedora 20 features some of the latest and best of what the open source world has to offer.

You can read more about this release announcement at below urls.

www.redhat.com/about/news/archive/2013/11/fedora-20-heisenbug-now-available-in-beta-release#!

lwn.net/Articles/573588/

From cloud and virt point of view, this release includes:

Secondly, selinux is celebrating its 10th year with an awesome how-to guide for SELinux policy enforcement ..

If you havent got ‘selinux’ yet, please go through the ‘visual treat’ here..

opensource.com/business/13/11/selinux-policy-guide

mount beautifully !

This is small tweak to display the output of the mount command in a more aesthetic way.

Until now, many of you would be using the mount command in a way that requires you to stretch your eyes to look at what exactly you want.

Instead you can use the pipe to pass the output of this command to another command : coulumn along with the usage of the ‘-t’ flag.

Below you can see the examples with and without the usage of : mount

mount_without_column

Now lets have a look at how this looks with : mount | column -t

mount_with_column

 

You can also use this to read and display output from files. Lets see how the output of /etc/fstab looks with and without the usage of columnt -t.
  • Output of fstab file without using columnt -t:
# cat /etc/fstab | grep -v ^#
/dev/mapper/vg_dhcp209191-lv_root /     ext4    defaults        1 1
UUID=9b14ad8f-93d9-432e-bcb0-94f012607328 /boot    ext4    defaults        1 2
/dev/mapper/vg_dhcp209191-lv_swap swap    swap    defaults        0 0
tmpfs        /dev/shm     tmpfs   defaults        0 0
devpts        /dev/pts    devpts  gid=5,mode=620  0 0
sysfs        /sys    sysfs   defaults        0 0
proc      /proc  proc    defaults        0 0
  • Output of fstab file with columnt -t:
# cat /etc/fstab | column -t | grep -v ^#
/dev/mapper/vg_dhcp209191-lv_root                          /                  ext4            defaults                   1           1
UUID=9b14ad8f-93d9-432e-bcb0-94f012607328         /boot           ext4            defaults                  1           2
/dev/mapper/vg_dhcp209191-lv_swap                      swap             swap         defaults                   0           0
tmpfs                                                                                /dev/shm    tmpfs           defaults                  0           0
devpts                                                                             /dev/pts       devpts        gid=5,mode=620    0           0
sysfs                                                                               /sys                sysfs         defaults                    0           0
proc                                                                                 /proc               proc          defaults                    0           0
So now you can read your files and command outputs in a better way.

Install bit torrent client ( transmission) for fedora ..

Friday or drive by post here 🙂

How to install and use bit torrent clients in fedora? its as simple as that: You need to install ‘transmission’ package to get bit torrent client for fedora.
Once you installed it, bit torrent client is ready to use for torrent action. You can either use ‘transmission” cli or GUI mode.

‘transmission-cli-2.80-2.fc19.x86_64’ provides ‘cli’ version of torrent client.

You can use above switches of the binary for torrent actions.

If you are interested in graphical utility of torrent client , its provided by ‘transmission-gtk-2.77-3.fc19.x86_64’ package :

You can either run :

#/usr/bin/transmission-gtk

or download ‘torrent’ file, then open it with ‘transmission’ :

You are done..

How to edit a kernel parameter in fedora >=18 (f-18, f-19..etc) versions? Or in grub 2 ?

Hmmm.. grub2 looks really strange to me ! .. In earlier versions of ‘grub’ it was really easy to manage. for example if you we want to edit a kernel parameter, get into /boot/grub/grub.conf and change the entry.. thats it.. but I failed to do that in my fedora 19 system with grub2.

This article may be a silly one for grub2 experts.. how-ever nothing stopping me to share it for newbies like me 🙂

Lets examine important locations of grub2.

Those are ‘/etc.grub.d/’ and ”/etc/default/grub’..

Lets see what are inside it:

So, grub2 have its scripts in more modular format as shown above.. Lets..

So, second location is ‘/etc/default/grub’ file.

Whats inside it ?

I would like to add a kernel parameter to my kernel command line.. may be ‘edd=off’ :

For that, I edited it in GRUB_CMDLINE_LINUX value..

Once you do that, you have to generate the new configuration by using grub2-mkconfig command..

How-ever the above output have to be recorded inside ‘/boot/grub2/grub.cfg’.. for that you can use -o switch of grub2-mkconfig as shown below:

Lets cross verify whether it reflected in the configuration setting by:

Coooooooool, hope it helps..

Analyse system boot up performance by ‘systemd’ or ‘systemd-analyse:’ in fedora

systemd-analyse binary has different options to list this: 2 of the interesting options are ‘time’ and ‘blame’

   ‘systemd-analyze time’ prints the time spent in the kernel before userspace has been reached, the time spent in the initial RAM disk (initrd)
before normal system userspace has been reached and the time normal system userspace took to initialize. Note that these measurements
simply measure the time passed up to the point where all system services have been spawned, but not necessarily until they fully finished
initialization or the disk is idle.

     systemd-analyze blame prints a list of all running units, ordered by the time they took to initialize. This information may be used to
optimize boot-up times. Note that the output might be misleading as the initialization of one service might be slow simply because it waits
for the initialization of another service to complete.