Dear Linux SysAd Blog Readers

Dear Linux SysAd Blog Readers,

To all my subscribers and readers, I do appreciate all your time reading my feeds from time to time. Thank you for all the comments, shouts, and emails that I have been receiving too. I also appreciate the nice chillers, stumblers and community diggers you have been contributing up until now. Those backlinks, blogrolls, relinks that you are sharing from your sites, I managed to have 268 feed readers and subscribers which started from 1st of July 2007 up to this date, I thank you for all that.

...

Honestly, now my mind suddenly just warped back into the black hole and forgot what to blog.

So I went back to my old Gmail and randomly selected one of my emails for today. And decided to publish this particular email:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Hi I came across your blog
http://ilovetux.com/2007/08/create-your-own-linux-os-distro-howto.html

I got the information exactly that I was searching ,I need some more information in case you know some thing then tell as per the instructions given on the revisor it is possible to create a distribution based on fedora I want to know is there any way this creation of DVD can be done without using revisor ,actually I want to understand this process of creation of installation media or ISO for my own customised linux tell me some keywords that I should look in for google

I don't want to use revisor that way I wont be able to know what exactly revisor did to create the installation media similar tool exist for Suse that is Kiwi
http://liquidat.wordpress.com/2007/06/22/kiwi-opensuses-re-spin-creator/
http://en.opensuse.org/KIWI

I am a learner and not much experienced in programming give me some links that might be relevant or google keywords to look in for .

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Sure, I gladly replied him back with

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

if you want to build your own custom linux, the best reply i can give to you right now is to use google to search for

linux from scratch

do let me know if you plan to publish your new linux ISO, i would love to download it and watch it grow from distrowatch.org too :)

thanks for visiting my site, i appreciate your support.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Again, I may not have all the time blog posting here, there, check spell that and this, and replying back to all your email requests, queries, comments due to some *time constraints but am still around here, working and blogging the alternative way, trying to have them one at a time and publish them one by one. I may not post from time to time but will do sooner or later.

Linux had invited us into one common IT place of linux advocacy and interests regardless of age, sex, religion, cultures, desktop and servers specs. I am glad to see that linux community had grown tremendously and still growing every day, well done.

Hope you stay tuned and see more of your visits from time to time.

Thanks for reading.

Cheers,
VeRTiTO

Proactive monitoring from linux terminal

As I was watching several google search keywords being used by most site visitors around this linux blog, I noticed several search keywords that led most users into this site

One of the recent google keyword search from CA,USA was:

~~~~~~~~~~~~~~~~~~~~~~~~~~~
linux watch ls directory
~~~~~~~~~~~~~~~~~~~~~~~~~~~

with equivalent google search URL:

google search keyword

and in turn, google replied with this URL

from one of my Linux SysAd blog entries as you can see.

However, the returned URL is about ls command usage but not watching directory and files proactively from display screen. Yes, it is somehow related but needs more command tweaking and another linux command.

So, I am creating this blog entry for monitoring directory and files proactively live from your display screen via command line terminal.

Here's several ways on how to watch live directory/files changes from your display screen.

Fire up your first terminal and issue
# cd /tmp
# watch ls -C

Then fireup your second terminal and issue the commands below
# cd /tmp
# touch A1
# touch A2
# touch Z1

During the creation of A1, A2, Z1 files using linux touch command, you need to switch and focus your screen display with the terminal which was first launched.

Here's a way to watch them change on the fly sorted by ctime or creation timestamp.

From the first terminal, issue
# watch ls -Cc

By default, 'watch' linux command refreshes every 2 seconds. You can modify it using -n watch parameter like so

# watch -n 0 ls -CC

which waits for 0.1 seconds for file changes to be displayed out from your screen terminal.


If you are only interested to file changes owned by user vertito, simply

# watch -n 0 'ls -Cc | grep vertito'


Note:
1. printing characters are being stripped by watch linux command
2. any terminal resize would not do screen repaint automatically but after the next watch update


Now, to watch your ethernet TX/RX packets from ethernet device using watch, simply

# watch -n 0 ifconfig eth0

The above is like the command line version of NIC network general properties in windoze. You can also use these when troubleshooting network card and ethernet link connectivity issues or any network congestion issue from your current broadcast network.


If somebody is transferring FTP files into one of your managed host or partition, or an external host is uploading large files into your shared SAMBA folder and you want to watch your current disk/partition space usage proactively while the transfer is occurring, simply

# watch -n 0 df -ah
# watch -n 0 du -sh


To watch your host memory and swap resources proactively using watch

# watch -n 0 free
# watch -n 0 cat /proc/swaps

partially similar to top linux command.


To watch your queued mail proactively from terminal (postfix or sendmail), simply
# watch -n 0 mailq


I guess I have monitored and reacted proactively from my blog site as well because of this entry name.

There's a lot more live monitoring of logs and statistics that can be combined with watch linux command, you can create your own combination of linux command and shell scripts too!

That's all folks, enjoy, thanks for the black box tip!

deleting new lines and return line from text file

How to delete new lines and return key characters from text file?
How to delete backspace and formfeed characters from text file?
How to delete horizontal tab and vertical tab character from text file?
How to remove backslash from text file?
How to delete specific set of characters from text file?

A sample text file.

# cat testfile.txt
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The quick brown fox blogs over the Linux SysAd.



The quick brown fox blogs over the Linux SysAd.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To delete new lines and empty lines from text file
# tr -d '\n' < testfile.txt

How to delete backspace and form feed characters from text file?
# td -d '\b' < testfile.txt
# td -d '\f' < testfile.txt
# td -d '\b\f' < testfile.txt

How to delete horizontal tab and vertical tab character from text file?
# td -d '\t' < testfile.txt
# td -d '\v' < testfile.txt
# td -d '\t\v' < testfile.txt

How to remove backslash from text file?
# cat testfile.txt
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The quick brown fox blogs over the Linux SysAd.
\
\\
\\\
The quick brown fox blogs over the Linux SysAd.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# td -d '\\' < testfile.txt
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The quick brown fox blogs over the Linux SysAd.



The quick brown fox blogs over the Linux SysAd.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


How to delete specific set of characters from text file?
# cat testfile.txt
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The quick brown fox blogs over the Linux SysAd.



The quick brown fox blogs over the Linux SysAd.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# tr -d '=aeiou=' < testfile.txt
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Th qck brwn fx blgs vr th Lnx SysAd.



Th qck brwn fx blgs vr th Lnx SysAd.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


For more string and character manipulation of text file, read more tr arguments from here.

Google chat setup using PSI howto

Related to my previous entry here, here's another blog entry on configuring your Google mail account to do Google Talk/Chat with your friends without having logging into your GMail (Google Mail) account from any internet browser.

PSI INSTALLATION STEPS:
~~~~~~~~~~~~~~~~~~~~~~~

Here are five easy steps on how to setup your PSI messenger to connect to Google Talk/Google Chat servers.

If you have not installed PSI yet, visit this link. Assuming you have successfully installed yum, follow the below easy installation steps and screenshots guides.

1. Launch PSI messenger. Click Account Setup as shown below.


2. Click Add button, enter your Google Chat Name to identify the PSI Group. Followed by your Gmail Account name or your GMail email address as shown below. Click Save.


3. Make sure you check the below similar option boxes. Enter talk.google.com as your connection server. Enter the same port number as shown below.


4. From PSI main menu, choosing Online would start and connect your PSI to the net. Click and enabble the PSI group name.


Clicking Online would prompt your for your GMail account password, enter as required.


PSI would then retrieve your existing GMail friends and contact from talk.google.com server. PSI would then display all your online and offline users from here.

Congratulations!!! You are now online with Google Talk using PSI messenger.

For more PSI info, visit PSI site here.

HTH.

Cheers

Related Posts:


How To See Invisible YM Users
How To Setup Chikka SMS Messenger using Kopete Messenger
How To Setup Chikka SMS Messenger using GAIM Pidgin
How To Block YM Messenger
How To Install GAIM Pidgin Messenger
How To Install KDE Kopete Messenger
How To Install AMSN Messenger
How To Setup and Install PSI Chat Messenger

PSI messenger - a truly promising open messaging application

In the Open Source world, linux gives us more freedom and alternatives on achieving things from simple to complex technical server and dsektop issues. Linux applications does not confine us into one corner spot of the room and learn from that corner spot alone all time through. Linux open source applications expands your knowledge from your own stand point of interest supported by worldwide community and not from a commercially grown application interests.

Here's another entry on how to install PSI on Fedora

What is PSI?
~~~~~~~~~~~~

This is the best description I could have from PSI application, a well defined description and application usage from both developer and user's stand point of view.

PSI description:
(lifted from PSI site)
Psi is the premiere Instant Messaging application designed for Microsoft Windows, Apple Mac OS X and GNU/Linux. Built upon an open protocol named Jabber, Psi is a fast and lightweight messaging client that utilises the best in open source technologies.

The goal of the Psi project is to create a powerful, yet easy-to-use Jabber/XMPP client that tries to strictly adhere to the XMPP drafts and Jabber JEPs. This means that in most cases, Psi will not implement a feature unless there is an accepted standard for it in the Jabber community. Doing so ensures that Psi will be compatible, stable, and predictable, both from an end-user and developer standpoint.

This does not mean that Psi will never have "cool new features". The dev team and community are power-users who look to Psi to keep up with the times. We always want to hear what the users of Psi would like, and if a feature that the dev team wishes to implement does not have an accepted standard, or would diverge from an existing one, we can work together to see the standards changed to accomodate everyone.


PSI INSTALLATION USING YUM:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

# yum -y install psi psi-i18n psi-icons


APPLICATION LAUNCH:
~~~~~~~~~~~~~~~~~~~

# psi

Perhaps you have been considering Jabber, but don't want to abandon your friends? Jabber technologies are highly extensible, so Psi is able to interoperate with other, proprietory messaging systems such as AOL's ICQ and Microsoft's Messenger. You can keep in contact with your friends, regardless of whether they use AIM, ICQ, MSNM or YM. It's even possible to use Internet Relay Chat! *

Unlike other IM clients, Psi is small, fast and responsive. It uses a graphical toolkit called Qt, which takes on the appearance of whichever operating system you run it on. For this reason, Psi doesn't use 'skins'. We'd rather it blend with your desktop like any other application.


PSI Screenshots:




Final Note:
~~~~~~~~~~~
PSI internet chat messaging works smoothly with KDE and GNOME. PSI has extensive features available at its early age. PSI presents these features in user friendly appearance schemes systematically done, avoiding complex program menu structures and program options. This approach makes PSI messenger fun and easy to use. PSI is on its early version state yet but had already established as a true and very promising open internet messaging application.

So watch out for PSI growth. Enjoy!

Related Posts:


How To See Invisible YM Users
How To Setup Chikka SMS Messenger using Kopete Messenger
How to Install and Setup Google Chat Messenger
How To Setup Chikka SMS Messenger using GAIM Pidgin
How To Block YM Messenger
How To Install GAIM Pidgin Messenger
How To Install KDE Kopete Messenger
How To Install AMSN Messenger

Google chat setup using GAIM Pidgin howto

As per request, here's an entry that shows how to setup your Pidgin GAIM to use your Google Talk or GMail account.

Pidgin man:
Pidgin is a graphical modular messaging client based on libpurple which is capable of connecting to AIM, MSN, Yahoo!, XMPP, ICQ, IRC, SILC, SIP/SIMPLE, Novell GroupWise, Lotus Sametime, Bonjour, Zephyr, Gadu-Gadu, and QQ all at once. It is written using GTK+.


FIVE EASY STEPS:
~~~~~~~~~~~~~~~~

1. Make sure you have the latest pidgin software. To upgrade your current GAIM application using Fedora yum, simply connect to the internet and issue

# yum -y upgrade gaim

2. Make sure you already have an existing GMail account. Launch Pidgin GAIM software. Add a new your GMail account by clicking Account menu from GAIM and selecting Add from one of the dropdown menu.

3. A new Add Account window would appear. Click Add button. Simply select Google Talk from one of the Protocol dropdown selections. Complete the other required fields like screen name and password as shown below. Remember to click the Save button.


4. Now, back to pidgin window, press Ctrl+A keys to view all your Pidgin current account settings. A new Account window will appear. From the list being shown from your screen, you should be able to see your newly added Google Chat Pidgin account that makes use of XMPP protocol.

5. To start using Google chat from Pidgin, simply check or tick the Enabled tick box from the leftmost part of your Google chat account and enter your password when prompted. From here, you can starting adding your GMail friends and contacts.

Enjoy!

For more pidgin info, visit here.

Linux command line shell variables defined

Reading daily doze of linux commands makes our memory to remember their command usage and command scopes. Doze of commands refreshes part of our linux brain to easily apply simple but useful linux commands when needed. Remembering those thousand of commands is not really an easy task specially most linux commands are not being used and applied on our daily linux work routines.

Here are a few doze of linux shell variables that might be helpful and useful to some bash shell scripting.

Usually, when creating shell scripts, we make use of user input variables or command line parameters that server as input arguments to shell commands or shell executable scripts. Using these variables provides us a way to determine shell program function execution and directly reference a submitted command line parameters.

Below are several linux bash variables that we can integrate when parsing user-input command line parameters.

$$

The above linux shell variable can be used to display and fetch current PID number of the current shell script.

How to know your current shell PID number from command line?

# echo $$
~~~~~~~~~~~~~~~
25341
~~~~~~~~~~~~~~~

Usage Application:
~~~~~~~~~~~~~~~~~~

On terminating and remembering the PID number of the current running shell program. A sample shell script usage of the above command would be

~~~~~~~~~~~~~~~~~~~~~
#/bin/bash
echo Current PID: $$
~~~~~~~~~~~~~~~~~~~~~

Next linux shell variable

When terminating a function, a proper way to determine if a function script had terminated properly is to determine its script exit code or status. This can be done by using the below linux shell variable

$?

Usage Application:
~~~~~~~~~~~~~~~~~~

When doing function or disk/file operations, or even executing another shell script, we can make use of this linux shell variable as shown below, which prints the exit code status of test_function
after finishing some stuff operations shown below.
~~~~~~~~~~~~~~~~~~~~~~~~~~~
#/bin/bash
function test_function {
# do some stuff
echo Function Exit Code $?
}
# call the function
test_function
~~~~~~~~~~~~~~~~~~~~~~~~~~~


Next linux variable

$0

This variable displays how the current shell program is being called. This could refer also the current path location where the program has been executed. We can also make use of this to test for any filename changes with the shell and/or any changes with the working folder of the file executable to verify if the current working folder or filename had been tampered or changed.

Usage Application:
~~~~~~~~~~~~~~~~~~

The below script checks if the script is being called from /tmp and the script name is test.sh

# cat /tmp/test.sh
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#/bin/bash
echo $0
if [ "$0" = "/tmp/test.sh" ]; then
echo "Good starting folder and still the same shell filename"
else
echo "Alert: Script Name and/or source folder changed!"
fi
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


Next linux command variable would be

$1
$2


The above linux shell variable refers to arguments or parameters being passed to current shell script:

Usage Application:
~~~~~~~~~~~~~~~~~~

# cat test.sh
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#/bin/bash
echo Parameter No. 1: $1
echo Parameter No. 2: $2
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

# ./test.sh firstname secondname
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Parameter No. 1: firstname
Parameter No. 2: secondname
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The above variable applies also to Nth variable.


The next linux shell variable:

$*

The above refers to all parameters or arguments passed with the current shell script

Usage Application:
~~~~~~~~~~~~~~~~~~

# cat test.sh
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#/bin/bash
echo Parameters Passed: $*
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

# ./test.sh Linux SysAd Blog
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Parameters Passed: Linux SysAd Blog
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Passing variables makes it easy for varying input arguments for a shell script. This approach flexes input entries for specific shell script. It can also be used to trigger shell functions and shell program directions as well.

Now, the below command refers to the total number of command line parameters or argument passed together with the shell script

$#

Usage Application:
~~~~~~~~~~~~~~~~~~

# cat test.sh
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#/bin/bash
echo Number of Parameters supplied: $#
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

# ./test.sh I have only 5 parameters.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Number of Parameters supplied: 5
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Another shell variable is

**

This shell variable when used displays all files and directory folders located from where the shell script was called.

Usage Application:
~~~~~~~~~~~~~~~~~~

# cat test.sh
~~~~~~~~~~~~~~~~~~~~~~
#/bin/bash
echo **
~~~~~~~~~~~~~~~~~~~~~~

Looks useless but serves its purpose when used well.

Here's a tip:

Pressing ESC+* from command line list down all available binaries from current PATH variable of current box which the current user can make use of.


Final Note:
~~~~~~~~~~~

These linux shell variable can be handy when creating varying input arguments with your shell scripts. Making use of these variables creates convenience on passing parameters to a shell script.

Redirecting shell program direction when using these variables would then be easier assuming a single shell script that does two (2) different functions. Simply pass a trigger word that would redirect the shell program to call for a particular shell function defined inside that script like so:

# ./test.sh trigger2

That does the linux shell task as expected.

Happy weekend!

ls - displaying directory contents in many ways

Here goes another tutorial that would uncover samples of using the most commonly used linux command using the command line terminal.

This linux blog entry covers the tutorial of using one of the simplest command line in linux terminal.

LS Tutorial - Display Files and Folders in Linux

ls is a linux command that is basically being used from command line terminal to list down directory contents. Directory contents can are linux files, it can be typical directory files, special files, directories, hard and soft links or any other device contents.

File items and directory folders are usually the contents of current working folder. Linux directory usually contains folder locations the probably contains zero or more files inside it, while linux files are files, hard or soft links to files or device that contains zero or more data contents when viewed or referenced from.

Here are more ls samples that might be helpful on learning this ls command.

How to list down all files and directory folders of current working directory.

# ls

How to list down all files and directories using ls a short format form


# ls -a

How to list down all files and directories using ls a short format form

# ls -la

Using the above two commands shows linux files and folders. In a long format, ls shows directory contents with their corresponding file attributes and file ownership and permissions, date/time stamps and filesize .

Most linux distro uses command aliases.

To print the current alias for ls, simply

# alias ls

Using the above command would show the current ls alias and ls parameters when issued directly from the command line. This goes to any other linux command aliases.

To continue with ls command, here's how to list down all directory contents excluding . and .. in a short ls form

# ls -A

Combining the previous two commands of using ls to show the long format form and all directory contents but without . and ..

# ls -Ala

To list down directory contents in a more human readable form showing sizes like 1K, 2M 3G file sizes

# ls -h
# ls -hal
# ls -halA

To list down directory contents without showing ownership and group names would be done respectively like so

# ls -aG
# ls -aGg


To list down directories and folders only in ls short form

# ls -d */

To list down directories and folders only in ls long form would be

# ls -dl */

To list down directories and folders start starts with d displayed in ls short form would be

# ls -d d*/

To list down directories and folders start starts with d displayed in ls long form would be

# ls -dl d*/

ls always shows directory contents in a colored ls alias fashion. To ignore and display directory contents without screen colors would be

# ls -la --color=never

To list down directory contents with reverse matching pattern and hide a specified patterns from being displayed would be

# ls --hide=v*
# ls --ignore=v*


The above list down all directory contents except the ones that starts with the letter v

To list down directory contents with numeric user and group IDs using ls would be

# ls -n

To list down directory contents with index number of each item would be

# ls -lai

To list down directory contents showing also the link reference rather than the link itself would be

# cd /dev
# ls -laL

To list down directory contents recursively would be

# ls -R

To list down directory contents sorted by modification time would be

# ls -t
# ls -lat

The default ls tab stop is 8, if you want to customize the ls tab stop, simply specify it like so

# ls --tabsize=16

To list down directory contents separated by comma in a short ls form would be

# ls -m

To reverse the sort ordering display of directory contents using ls would be

# ls -r
# ls -lar

HTH

Control of alternative linux executables

Here are simple tips on controlling which executables would be executed by your linux box when issued from command line terminal.

There are several ways to specify and control which binary executable file or linux shell command would be executed by your system when issued from the terminal.


SCENARIO APPLICATION
~~~~~~~~~~~~~~~~~~~~

This blog entry assumes the possible scenarios relating to this linux blog entry:

a. you just resume to your new job with these linux boxes and you found out that some binaries were installed manually from tar ballz (tar.gz) and some were from rpm (rpm) binary package installer

b. the linux box uses both opensource binary package version and the package distributed by commercial company, like for Java binaries.

c. a previous sysad created an executable with an exact filename similar to linux built-in commands.

d. simply you want to know specify which binary executables you want to execute


Let us assume that we currently have two binary executable files named nagios, which are currently located from two different location ofcourse.

# which dir
/usr/bin/nagios
/usr/local/bin/nagios


Here are some alternative approach on how to specify which binary file location to go into when executing a linux binary or executable file.


First scenario approach
~~~~~~~~~~~~~~~~~~~~~~~~

Be in charge of your linux bash environment. This includes setting all the needed environment variables into your desired needs. Reordering of default PATH shell environment from current user account is also advisable .

# echo PATH

Considering the two binary nagios path locations

/usr/bin/nagios
/usr/local/bin/nagios

And assuming you want your system to look first for /usr/local/bin/, simply specify and change your system PATH environment variable and make sure /usr/local/bin comes first before /usr/bin before executing the duplicated binary executable like so

# export PATH=/usr/local/bin:/usr/bin
# nagios


Second scenario approach:
~~~~~~~~~~~~~~~~~~~~~~~~~

Make use of linux command name aliasing. Linux bash aliases can be instructed to remember a particular path location when executing a specific linux command. This also applicable to specify further binary arguments when calling a default binary executables.

# alias nagios='/usr/local/bin/nagios'
# nagios

To specify additional argument for a binary
# alias nagios='/usr/local/bin/nagios --whatever'
# nagios

To print all linux aliases and verify the above specifed binary path location alias

# alias
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
alias nagios='/usr/local/bin/nagios'
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


Third scenario approach
~~~~~~~~~~~~~~~~~~~~~~~~~

Alternatives man definition:
alternatives creates, removes, maintains and displays information about the symbolic links comprising the alternatives system. The alternatives system is a reimplementation of the Debian alternatives system. Alternatives was rewritten primarily to remove the dependence on perl; it is intended to be a drop in replacement for Debian’s update-dependencies script.

It is possible for several programs fulfilling the same or similar functions to be installed on a single system at the same time. For example, many systems have several text editors installed at once. This gives choice to the users of a system, allowing each to use a different editor, if desired, but makes it difficult for a program to make a good choice of editor to invoke if the user has not specified a particular preference.

The alternatives system aims to solve this multiple executables issues by using symbolic links to specify default command location using linux command alternatives.


Now, to install and add both nagios alternatives to alternatives config choices, simply

# alternatives --config nagios
# alternatives --install /usr/local/bin/nagios nagios /usr/local/bin/nagios 1
# alternatives --install /usr/bin/nagios nagios /usr/local/bin/nagios 2

To view current nagios alternatives config
# alternatives --display nagios

To view and select which binary nagios binary for linux to execute when issued from CLI
# alternatives --config nagios

Alternatives prioritizes binary command execution using alternatives command as shown above.


Final Note:
~~~~~~~~~~~

As you can see, there are lot of alternative ways to approach an issue using linux tool sets. Linux is quite powerful specially on these scenario on customizing basic tool command sets up to custom made kernels, that is why OpenSource tools are quite powerful and would continue to be so.

HTH
Appreciate your visit here, thanks for the tip!

Searching using whereis linux command

Now, another simple linux command for locating binary, source and manual pages using whereis.

From recent linux 'which' blog entry, here is another way to find and locate the location and full path of a particular binary, man pages and sources of a given program argument. Whereis locates the binary from the standard linux binary locations.

Whereis man description says:
whereis locates source/binary and manuals sections for specified files. The supplied names are first stripped of leading pathname components and any (single) trailing extension of the form .ext, for example, .c. Prefixes of s. resulting from use of source code control are also dealt with. whereis then attempts to locate the desired program in a list of standard Linux places.



Whereis Usage and Explanation:
~~~~~~~~~~~~~~

# whereis cat
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cat: /bin/cat /usr/share/man/man1p/cat.1p.gz /usr/share/man/man1/cat.1.gz
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

From the above result, Whereis shows
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a. cat binary location is /bin
b. cat man and source pages are currently located in
/usr/share/man/man1p/c
/usr/share/man/man1/c
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


More Whereis Usage and Examples:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To locate a binary or executables location only using whereis
# whereis -b cat
~~~~~~~~~~~~~~~~~~~~
cat: /bin/cat
~~~~~~~~~~~~~~~~~~~~

To locate and search from manual pages or section of a binary using whereis from terminal
# whereis -m cat
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cat: /usr/share/man/man1p/cat.1p.gz /usr/share/man/man1/cat.1.gz
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To limit the place where whereis would search location from
# whereis -B /sbin -b cat

which shows no result since we know that binary cat is located from /bin folder location and not /sbin which was specified above.

Now, here's another whereis example application

# cd /tmp
# touch cat
# ch700 cat
# whereis -B /tmp -b cat
result:
~~~~~~~~~~~~~~~~~
cat: /tmp/cat
~~~~~~~~~~~~~~~~~

# whereis abc123
# whereis cat echo

# whereis whereis
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
whereis: /usr/bin/whereis /usr/share/man/man1/whereis.1.gz
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

HTH

Witchy which linux command

Here's a simple linux command the give you the full path of of linux binary or executable command.

Which definition:
~~~~~~~~~~~~~~~~~~

Which Linux command shows the full path of any binary or shell command when executed. Which does the full patch searching by looking from the linux environment PATH variable. Which command can take one or more argument for processing. This 'which' linux comamnd follows the command line format as shown below:

which command1 command2


To list out your PATH environment variable from command line

# echo $PATH

Alternatively, you can grep PATH variable from your current environment shell like so

# set | grep PATH


Which Usage
~~~~~~~~~~~

Let us assume that you have a command named fixit that was installed from tar ball (tar.gz) and from rpm package (rpm). On which, fixit was probably installed into /usr/bin and /usr/local/bin .

To execute the command, simply issue

# fixit

The problem with this command is you don't know which binary has been executed by the system.
One way of resolving this issue is using which linux command by doing so

# which fixit

which then tells you which binary would be executed if fixit was issued from ther terminal. Which linux command also tells your the full path location of the command argument.

Final Which Note:
~~~~~~~~~~~~~~~~~

Using which, you can then know where would be the binary path location is when a command or executable shell would be executed. Which linux command is installed in Fedora by default system tools installation.

More which command line examples:
~~~~~~~~~~~~~~~~~~~~

# cd /home/me
# chmod 700 fixme
# which ./fixme
~~~~~~~~~~~~~~
/home/me/fixme
~~~~~~~~~~~~~~

# which which
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
alias which='alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde'
/usr/bin/which
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# cd /tmp
# touch cat
# chmod 700 cat
# which ./cat
~~~~~~~~~~~~~~~~~~
/bin/cat
~~~~~~~~~~~~~~~~~~

# which echo dir
~~~~~~~~~~~~~~~~~~~~~~~~~~~
/bin/echo
/usr/bin/dir
~~~~~~~~~~~~~~~~~~~~~~~~~~~


HTH

NeroLinux - diehard Nero burning software

For die-hard Nero burning software fans, Nero burning software also comes in Linux.

Nero Linux is a flexible application, which supports all important features of Nero Burning ROM on Linux Systems.

From Nero site:
Nero Linux 3 is the definitive burning application for the Linux operating system. Based on the award-winning Nero Burning ROM 7 platform, Nero Linux 3 is the most powerful and versatile burning application available for Linux, and the only application to offer Blu-ray Disc and HD DVD data burning support.

Main Nero for Linux features:
* Enjoy the same functionalities as in Nero Burning ROM 7
* Burn data using any optical disc format, including CD, DVD, Blu-ray Disc, and HD DVD
* Ensure a quick and easy setup using SmartDetect automatic drive support
* Take control of your music collection with integrated audio capabilities including high speed digital audio extraction and FreeDB to automatically obtain disc information over the internet

Nero Linux is able to burn the following formats:
- Data CDs and DVDs (using ISO9660, UDF and UDF/ISO9660 Bridge)
- Data HD DVDs and Blu-Ray discs (UDF)
- Bootable CDs/DVDs using the El-Torito standard
- Audio CDs from various audio formats
- Mixed-Mode CDs and Enhanced CDs (CD EXTRA)
- Disc Images (ISO, NRG and Cue Sheets)
- DVD-Video and miniDVD
- Multisession discs


NeroLinux also uses the embedded API from the widely used Nero burning software for windows. Another good thing about Nero's burnign software is simple but thourough application guide that comes from the installer which is also available from the web. If you wish to know more of its documentation and application operation, you can visit them here.


NERO FOR LINUX INSTALLATION:
============================

If you wish to give NeroLinux a try, download the rpm package NeroLinux in full trial version from here.

After downloading the package, simply use the rpm binary installer to install the package like so:

# rpm -ivh nerolinux-3.0.1.3-x86.rpm


NEROLINUX APPLICATION LAUNCH
============================

# nero


NeroLinux works in Fedora, see my own screenshots:
The first two initial screenshots would be prompted after a fresh installation.


Now, here comes my selection of files of data burning.



Yes, it is a full Nero for Linux version that offers a full feature Nero burning software in 30 days trial mode!

HTH

All products, trademarks, and companies mentioned here are all managed by their own respective owners and/or companies.

Google Sky - Explore and Rediscover the Sky

Now, I have a chance to post a 3D rendering related linux blog entry here that explores more of the Stars and Sky using Google Earth.

Three weeks ago, Google launched the latest addition and highlight features with Google Earth. The feature addons is being called Google Sky and is part of Google Earth version 4.2.

Google Sky button is available from one of the top menu palen from Google Earth application. Google Sky is referreing name on visualizing stars and galaxy using Google Earth. Impressively, this Google Sky enables you to visit any stars and galaxies around the universe, as if they are near you and you were travelling faster than the speed of light!

Google Sky also allows you to select from several variety of constellations, stars, planets, moon, galaxies, astronomy, and more technical info of current view such as object distance, size, diameter, history and life of the galaxy object being viewed.

GOOGLE EARTH INSTALLATION
=========================

Download the latest Google Earth from here.http://earth.google.com/download-earth.html

For more Google Sky info and feature flash demo, visit the site from here http://earth.google.com/sky/skyedu.html

After downloading GoogleEarthLinux.bin, simply

# chmod 700 GoogleEarthLinux.bin
# ./GoogleEarthLinux.bin

GOOGLE EARTH BINARY LAUNCH:
===========================

# googleearth

More Google Sky Video/Audio Brief Demo:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

My own Google Sky screenshot using Google Earth:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~




Watch a Fascinating Google Sky Video Demo from YouTube files:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you can run Google Earth from your desktop, you can also run Google Sky pretty well.

I am giving the latest version of Google Earth and Google Sky feature an additional 5/5 feature rating!

Well done Google guys!

All trademarks and products mentioned here are all managed by their own respective company and owners.

Celestia - 3D Earth and Sky visualization

Here's another linux application that that lets you explore the sky, planets, stars, galaxy and universe in three dimensions (3D), also an alternative for MS Visual Earth.

Celestia is a real-time space simulation which lets you experience the universe in three dimensions. Celestia does not confine you to the
surface of the Earth only, but Celestia allows you to travel throughout the entire solar system, to any of over 100,000 stars, or even beyond the galaxy.

The Celestia has several features, one of them is exponential zoom feature that lets you explore space and galaxies across a huge range of scales and from galaxy clusters down to spacecraft only a few meters across. A 'point-and-goto' interface makes it simple to navigate through the universe to the object you want to visit, all these are displayed seamlessly in 3D rendered graphical display from GNOME or KDE.

Celestia is expandable. Celestia comes with a large catalog of stars, galaxies, planets, moons, asteroids, comets, and spacecraft. If that's not enough, you can download dozens of easy to install add-ons with more objects.

I have successfully installed Celestia from my intel-based motherboard and video adapter. And I have to say the 3d graphics was rendered by Celestia in an impressive seamless way making use of my 3d-enabled intel based vga adapter.


CELESTIA INSTALLATION
=====================

Ce