Mar 26, 2012

5 Tips and Tricks for Using Yum

If you're using one of the Fedora/Red Hat derived Linux distributions, odds are you spend some time working with Yum. You probably already know the basics, like searching packages and how to install or remove them. But if that's all you know, you're missing out on a lot of features that make Yum interesting. Let's take a look at a few of the less commonly used Yum features.

Yum comes with a lot of different distributions, but I'm going to focus on Fedora here. Mainly because that's what I'm running while I'm writing this piece. I believe most, if not all, of this should apply to CentOS, Red Hat Enterprise Linux, etc., but if not, you may need to check your man pages or system documentation.

Working with Groups

If you use the PackageKit GUI, you can view and manage packages by groups. This is pretty convenient if you want to install everything for a MySQL database or all packages you should need for RPM development.

But, what if you (like me) prefer to use the command line? Then you've got the group commands.

To search all groups, use yum group list. This will produce a full list of available groups to install or remove. (Yum lists the groups by installed groups, installed language groups, and then available groups and language groups.)

To install a group, use yum group install "group name". Note that you may need quotes because most group names are two words. If you need to remove the group, just use yum group remove "group name".

Want to learn more about a group? Just use yum group info with the group name.

Love the Yum Shell

If you're going to be doing a lot of package management, you want to get to know the Yum shell.

Just run yum shell and you'll be dumped in the Yum shell. (Which makes sense. It'd be weird if you got a DOS prompt or something...) Now you can run whatever Yum commands you need to until you're ready to exit the Yum shell.

For instance, want to search packages? Just type search packagename.

Here's the primary difference, when running things like install or remove, Yum will not complete the transaction immediately. You need to issue the run command to tell Yum to do it. This gives..............


Mar 20, 2012

Simple command-line tricks

It has been a while since we had a column dedicated to useful command line tips. This week we will cover some simple, but often useful, command line tricks.

This first command will play all of the MP3 files in my Music directory, including all of the files found in sub-directories. It uses the find program to locate all MP3 files in the music directory and passes them off to the mplayer multimedia program to be played. The "-iname" flag tells find to ignore the case of the file name so that myfile.mp3 will be treated the same as MyFile.MP3. The braces, {}, toward the end of the command represent a file located by the find program which will be handed over to mplayer.
find ~/Music -iname "*".mp3 -exec mplayer {} \;
Sometimes people send me archives or CDs which contain files with improper access permissions. The first of the following two commands locates all folders in the current directory and grants my user full access to them. The second command locates all files in the current directory (and sub-directories) and provides read and write access to them without making them executable. The "-type" flag lets us select whether we are operating on a (d)irectory or on a (f)ile. The chmod program then applies the proper permissions to each directory and file.
find . -type d -exec chmod 700 {} \;
find . -type f -exec chmod 600 {} \;
When we first install our operating system we sometimes need to change the system date. Or, if our computer clocks don't automatically change to accommodate daylight saving time we might need to make adjustments. From the command line this is fairly straight forward. The following command sets the current system time to noon.
date -s "12:00"
Please note we will need to have administrator access to change the date and time. The next command tells the machine to change the clock to March 24, 12:30.
date -s "Mar 24 12:30"
They say timing is everything and it is useful to be able to schedule commands to be run at a later point in time. The following command will cause the sound file alarm.wav to play at 5pm.
echo mplayer alarm.wav | at 17:00
The at command can also be used to run scripts at a given time as in the following example where we run my_script at 11:40.
at 11:40 < my_script
Last, but not least, this is a very handy command to have when an application needs to be terminated. Let's say we have the VLC multimedia player running and, for some reason, we need to close it. Rather than look up its process ID and terminate the program with the kill command we can use a program called pkill to shut down the process by name.
pkill vlc
The command line is very flexible and often useful, not only for complex tasks and processing information, but also for common day-to-day activities.


Mar 18, 2012

Linux Tutorial -Using the Secure Shell

Using the Secure Shell  Source:

Secure shell, specially the OpenSSH implementation of secure shell, is an important and valuable tool. This holds true largely because of the security it provides us for common tasks, but also because OpenSSH is so portable, enabling it to function on most modern operating systems. OpenSSH was originally forked from OSSH and developed for the OpenBSD operating system. Since its début in 1999, OpenSSH has been ported to Linux, to other BSD projects and to proprietary operating systems. Chances are if you're reading this from an open source operating system you have an OpenSSH component installed.

What's so important about OpenSSH? It used to be most network services sent their data in plain-text, completely open for anyone to read. While this was fast and convenient (and easy to debug) it wasn't secure. Logging into a remote machine meant sending usernames and passwords over the lines without hiding them in any way and transferring files in the open made it fairly easy to intercept them. OpenSSH encrypts its traffic, preventing people from listening in and gathering your login credentials or copies of any files you're sending over the network.

All of this may sound a bit abstract so I'd like to share a handful of examples of how OpenSSH can be used to communicate with a remote machine. In the following examples I'll be communicating with a remote server named "harold". For these examples to work the remote machine, harold, must be running the OpenSSH server and be able to accept connections on port 22.

Perhaps the most common usage of OpenSSH is logging into a remote machine to run command-line programs. System administrators often perform updates, check logs and change configurations this way. To do this we run

     ssh harold

The above example is secure shell invoked in its most simple form. Should we be connecting to a server where our username is different than our username on the local machine we can use the "-l" option. For example, if we wish to login to the remote machine as the user "susan" we would run

     ssh -l susan harold

In both cases presented above we will be prompted for a password and then given a terminal prompt on harold. When we are finished working on the remote server we can run "exit" to return to working on our local machine.

Another common usage of OpenSSH is the transfer of files between computers. There are two ways to do this. The first is to set up an interactive connection to the remote machine using the sftp command. A sftp session works much the same way as plain FTP, providing an interactive experience, but sftp encrypts the traffic between the machines, including our password. To start a secure file transfer session we use

     sftp harold

Alternatively, if we have a different username on the remote host, we can use

     sftp susan@harold

When using sftp we terminate the secure session using the "quit" command. If you're not familiar with using command line file transfer programs, there are graphical clients, such as gFTP or Filezilla, that make the process more intuitive. Another way to transfer files is with the secure copy command, scp. The scp command works much the same way as the "cp" command line program, but with the ability to work over a network. In the following example we copy a file, test_file.txt, to our home directory on harold.

     scp test_file.txt harold:test_file.txt

As with ssh and sftp we can send data to the remote machine as another user:

     scp test_file.txt susan@harold:test_file.txt

In other instances we may wish to copy files to a remote directory besides our home. In those cases we can specify the directory we want to use after the server name. This example copies our text file to our Work directory on the remote computer:

     scp test_file.txt harold:/home/jesse/Work/

The scp command works the other way too, allowing us to copy remote files to our local machine. In this example we copy a text file from harold and save it in our current working directory.

     scp harold:test_file.txt local_copy.txt

Sometimes administrators find themselves wanting to perform the same commands on multiple remote machines. There is a handy tool called ClusterSSH which will connect to several remote servers and send commands we type once to each machine. Bill Childers has a good tutorial on setting up and using ClusterSSH. I recommend reading it if you find yourself managing multiple machines.

Mar 14, 2012

Indian Railway Budget (रेल बजट) 2012

Indian Railway Budget 2012

रेल बजट 2012

Today Railway minister Mr. Dinesh Ttrivedi is started  presenting Railway Budget at Rail Bhawan . All eyes are on how he deals with Railway Security and Fares.

On his Speech Travedi Said 
  • Emphasis will be on better Railway infrastructure.
  • Railway Security is our prime concern
  • Gross budgetary support of over Rs 7.35 lakh crore for Railways
  • Rs.5.60 lakh crore required for modernization 
  • Railways to grow at 10% annually
  • Annual Plan for Railway for 2012-13 is at highest ever Rs 60,100 crore
  • Propose Rail Regulator to enhance Security
  • Anil Kakodkar to head new railway safety authority  
  • Urgent need to connect to northeast and J&K
  • Target should be zero death
  • Aim to upgrade 19,000 km of tracks in five years 
  • Pending Projects is 487 lack of funding
  • 85 new line projects to be introduced
  • Electrifications of  6500 kms 
  • 1000 new Railway Stations
  • Collective responsibility of Indian Parliament to make the Railways to be the best in the world
  • upgrading technology to increase speed of trains
  • Train will run @ 160km/hr 
READ More at Indiasuperphone

Mar 11, 2012

Linux Mint 12 LXDE

Linux Mint after successful release of Linux Mint Gnome Edition released Linux Mint 12 LXDE  Edition which a lightest one. This also includes Codecs to play media  files out of box.

Who Should USE
  • Beginners
  • Who Want Fast Desktop
  • Old harware

Screenshot of Linux Mint 12 LXDE :

System requirements for Linux Mint 12 LXDE
  • x86 processor
  • 256 MB RAM
  • 3 GB of disk space
  • Graphics card capable of 800×600 resolution
  • CD/DVD drive or USB port
Installation is simple just download the iso image  and  burn to CD or create LIVE USB  using software
'Startup Disk Creator' or 'UNetbootin'.

Download ISO Platform : 32 bit  Size : 657M

Quick Review :
Its damn fast ,detected all hardware of my laptop Acer Emachine E732Z, till now not a single crash, it will be so early to say it stable as I am using for one day.

Please Share your Experiences through comments.