Thursday, April 4, 2013

What version do I have to start learning linux?

Q. Which version do I have to start learning linux? What version is commonly used in the enterprise? Do all Linux versions have the same command? What is the difference between the versions of linux?

A. Any. All.

Redhat, Debian, and Ubuntu are common in enterprises. CentoOS is a free version of Redhat.


What is the command to know the linux version i am using?
Q. I am using a Linux server in command mode, i dont know which linux i am using ie whether it is Fedora Core 1,2,3 or Redh Hat linux Enterpirse or Linux 9.0 Version??

A. username@machine> uname -a
Linux test_machine1 2.4.21-4.ELsmp #1 SMP Fri Oct 3 17:52:56 EDT 2003 i686 i686 i386 GNU/Linux

In this example, the Linux kernel version is 2.4.21-4.

To obtain the Linux glibc version, type the following at the shell command prompt:

username@machine> rpm -q glibc

Two alternative methods to obtain glibc version information:
username@machine> /lib/ | head -1
GNU C Library stable release version 2.3.2, by Roland McGrath et al.

username@machine> getconf GNU_LIBC_VERSION
glibc 2.3.2

If you are using a RedHat Linux distribution, you can find the RedHat release by typing:
usename@machine> cat /etc/redhat-release
Red Hat Linux release 9 (Shrike)

Where do I find source code of linux commands?
Q. Linux commands like cp, dir, ls, shred, man (etc...) are nothing but programs (hopefully all written in C). I would really like to know exactly how they work (and make a few modifications to some) so I need their source code...
Can you tell me where to find source code of linux commands?
Thank you in advance!

A. In general there are several places you can go to get the source for these commands. This is mostly because there can be several different implementations of the commands.

1) The company who distributed your version of Linux. Most versions of these types of commands are under the GPL and as such the person or company who gave you the executable has to make a copy of the source code available to you. Usually these are released as source rpms, and some times come on one of the CDs or DVDs that you used to install Linux with. You can often find them on the web too.

For example the RHEL5 Server source rpm (SRPM) is

Most of the time your distribution will have a tool like yum to install these and other rpms for you.

GNU probably wrote the commands that are on your distribution of Linux, although a few very specialized distros use different implementations of the commands (Usually busybox but this is really rare).
has instructions on how to download a very recent copy of the code, which may be much much newer then the version currently installed on your computer.


Some shells, like tcsh and csh have their own implementations of these commands built into them. This is because it is faster to run the command as part of your shell then to fork and exec a new command. So if you do change them be sure to check that you are actually running your updated version. BASH usually does not play these games but you can always check by running which followed by the name of your command.

Nec Projector Review

Plastic Shed Reviews

Ati Graphic Reviews

Nurse Uniforms Reviews

Cabochons Reviews

Inflatable Water Slides Reviews

Barcode Scanner Reviews

No comments:

Post a Comment