Webblog for Open Source

Useful Vi commands

2009-12-01T17:01:00.004+05:30

Since last few weeks I've to use VI editor a lot from different platforms. Linux side its OK to use VI as so many developers has contributed and changed a lot things in VI but for other platforms (just few name to - AIX, Solaris) using VI is literally pain. Everytime when I wanted to add, edit, remove characters/words/lines I landed in situation where I've to undo all my changes & had to start the same boring things again. After googling I found VI's cheat sheet which's extremely useful if you're hard core VI fan or if I take it on other way then "If you don't have any choice (like me)". One link which I referred: http://bullium.com/support/vim.html. If you don't wann a scan complete list then few commands must to keep handy:

:q! - exit without saving changes
:wq! - exit with saving chages //! is for confirmation
h - characters to the left
l - characters to the right
k - line upward
j - line downward
/pattern - to search forward e.g. /nishit
?pattern - to search backward e.g. ?nishit
dd - delete current line
:d - delete current line
x - delete current character
u - undo the change

Keeping alive this blog with new post, where are you folks?

Different Types of Runlevel and Their Uses

2009-02-19T16:25:00.003+05:30

Hi Guys,

Runlevel: runlevel decided when your machine will start then it will be in enter
in which mode/runlevel .so each runlevel have their own functionality

1)runlevel 0(zero) : runlvevel zero is deoted that your machine is going to be shutdown
once you set this run level in "/etc/inittab" file your machine wll start
and shutdown

2)runlevel 1(one): if runlevel one is set in "/etc/inittab" file then your machine will
enter in single user mode where you have only limited command support like which you can
see the TAB key. use of this run level is for troubleshotting only but only standalone machine
not the networking level.

3)runlevel 2(two): if runlevel two is set in "/etc/inittab" file means it supports some
extra command but not on networking level . in all things same as runlevel one

4)runlevel 3(three): this is most advanced mode if set in "/etc/inittab" means it support
additional commands as well as support networking command also. means we can also solve
networking problem but only in comand level it will not direct enter in GUI level

5)runlevel 4(four): this is same as runlevel 3 but support some extra command

6)runlevel 5(five): this is most important mode/runlevel if set in "/etc/inittab" file
then after boot the machine it will direct enter in the GUI mode.
so the GUys who fear with CUI they can use that mode as default support all things
for troubleshottings

7)runlevel 6(six): once this runlevel set in "/etc/inittab" you machine will be reboot
number of times as when you started until you not change run level.

NOTE: 1) Don't set runlevel 0 and 6 in inittab file
2) Runlevel either should be 3(for CLI) and for 5(GUI)
3) Don't mak habit to play with "/etc/inittab" file

How to See what my current runlevel---->

1) simply type the command "runlevel" from shell
it will display the two character like this may be
N S --> means first character show your previous rubnlevel and second character show your present/current runlevel
like

3 5---> 3 was my previous runlevel and i am presently working in runlevel 5

How to Change the runlevel:
As i discussed above that file "/etc/inittab" open it
and see one line only

id:3:initdefault here 3 denotes your are in runlevel

change it whatever you want (but don't be 0 or 6 otherwise you have to enter in single user mode for solving that)

save file and reboot

if you have any query, contact Ajay@91-9971874367
Thanks
Ajay

How to crack the root(administrator) password in Linux

2009-02-18T12:02:00.003+05:30

Hi Guys,

you can crack the root(Administrator) password by using the following method

Method 1)
when Linux machine started on boot menu selection screen select the o/s type by using the arrow key and press Escape and then

1) press E (for enter in Edit mode )
after pressing E the three line will be appear select second line which is known as
boot or run level line and come at the end of line and
2) Write S
3) press b (for boot the machine in single user mode)

after entering the single user mode shell will be appear like this

sh-3.02#

then use the command "passwd" for changing the root password

NOTE: but this method will not work if somebody set the grub(grand unified boot loader) password
so for that either you should have the GRUB password or you have to follow the below method 2

Mthod 2)

For cracking the password of root when you don't have grub password then you need either
bootable linux floppy or Linux cd 1
1) enter the cd and on main menu donot press anything just type the command " linux rescue" and enter
2) then you will be in rescue mode by following some normal option which you can give answer easily
3) and same shell will appear

and type the command "passwd" (for changing the root password)

Thanks ,
Ajay

Sharing/accessing directories through Samba

2009-02-17T15:46:00.005+05:30

To add directories and make it shared through samba:

1) Go to /etc/samba directory
[root@nishit ~]# cd /etc/samba
2) open smb.conf file
[root@nishit ~]# vi smb.conf
3) Add these lines at last in file (say you want to share /home/user/Good directory)


path = /home/nishit/Good  //full path to the directory
public = yes              // make it global accessible
writable = yes            // provide write permission
printable = no            // Specify Yes if you want printer 
                             sharing.

4) Restart samba services
[root@nishit ~]# /sbin/config smb restart

When you install & configure samba server first time on linux (now a days all linux distribution comes with samba installed), you also need to specify for which user you want enable/use samba server. Since Linux is very strict about security, it wont enable samba server for all users available in Linux machine. Use this command to add user for samba server:

smbpasswd -a {username}

e.g. if you want to add nishit user (already available in Linux machine) then
[root@nishit ~]# smbpasswd -a nishit

How to do Inter Thread Communication ???

2009-02-16T18:42:00.004+05:30

In this thread how to do inter thread communication will be discussed.
For each of the way some example and explanation will be required.

These are the possible ways to do so..

shared Mamory
Port based communication
sockets
message queue
Distributed Objects.

NOTE: Please append this thread with your comments and knowledge base.

Mounting Flashdrive On FreeBSD Machine..!

2009-02-16T18:24:00.004+05:30

I have tried several combination of command to mount usb on FreeBSD.
Finally I had googled out following command for mounting flash drive on the FreeBSD

mount_msdosfs /dev/da0s1 /mnt/usb

This command will work fine...

Free Utilities..

2009-02-16T18:14:00.007+05:30

1) Free PDF Printer

Hi Folks,

look at this link if you are searching for PDF Printer.

http://www.bullzip.com/products/pdf/info.php

Its a Freeware and Light weight too !!!Enjoy...

2) Gnome Partition Editor

Looking for the free partition manager....

GParted is an industrial-strength package for creating, destroying, resizing, moving, checking and copying partitions, and the file systems on them.
http://gparted.sourceforge.net/

Download the Iso burn and use it.

NOTE: Please add other such free utilities in this thread..

Fedora 10 Vs Fedora 9

2008-12-27T01:38:00.000+05:30

After a long wait Fedora 10 was out in November, the whole open source community is waiting for this event. I downloaded and install fedora 10 CAMBRIDGE, also I tested the different features. First of all I like to say fedora 10 shutdown time is more than that of fedora 9. also the biggest and most remarkable thing is ONE CANT LOG IN AS ROOT IN GNOME OR KDE LIKE A NORMAL USER, this thing really freaked me out, means no GUI for root. Rest every other features are like fedora 9 ya better security better file sharing and management is there but all at some cost, will update soon, ya one more thing, one cant run ns2 by the normal method posted under this blog earlier. there is a patch for that refer to this link NS 2 PATCH

Fixing the MBR in Vista

2008-09-23T19:10:00.001+05:30

Scenario

Vista installed on the system. and you have installed any linux on the same system and somehow linux boot partition got affected or u have deleted and you need to fix this issue.

Solution

1)in case of vista.

-boot from the dvd of the windows vista gotto repair your computer menu

-select windows vista and select command prompt

use following command

bootrec.exe/fixmbr

2)in case of xp

-goto R option and

use fixmbr command

NS2 installations for Dummies

2008-03-15T00:15:00.000+05:30

How to install NS 2 on Linux, The step by Step Procedure
Step 1:Get NS2 All in one package from the below link or by clicking here http://sourceforge.net/project/showfiles.php?group_id=149743&package_id=169689&release_id=537005
Step 2:Copy the tar file in /home/
Step 3:Extract the tar file located in /home/ #tar -zxvf
Step 4:#cd
Step 5:#./install /* This will run the install Script, wait for the output */
Step 6:Now it is the time for setting environment variable, Copy the message displayed after running the above commmand to a text file else copy and paste this in a new text file
*****************************************************************************************
PATH=$PATH:/home/ns-allinone-2.31/bin:/home/ns-allinone-2.31/tcl8.4.14/unix:/home/ns-allinone-2.31/tk8.4.14/unix
LD_LIBRARY_PATH=/home/ns-allinone-2.31/otcl-1.13:/home/ns-allinone-2.31/lib TCL_LIBRARY=/home/ns-allinone-2.31/tcl8.4.14/library
export PATH
export LD_LIBRARY_PATH
export TCL_LIBRARY
*****************************************************************************************************
Step 7:save the file as ns2.sh
Step 8:copy the file into /etc/profile.d/
Step 9: either restart the machine or relogin
Step 10:Now run these commands #cd ns-2.31/ #./configure #make #make clean #./validate
Step 11: all done , just type ns at terminal e.g. #ns % and it is ready !
Enjoy simulating networks, protocols whatever you like, All the Best !

Mounting Using Usb Flash drive in red hat linux 9

2008-01-22T15:39:00.001+05:30

Dear Friends,

use this command for mounting usb drive in linux ..

1)cd /mnt
2)mkdir usbdrive
3)mount /dev/sda1 /mnt/usbdrive

Enjoy !!!!!!

Removing installed RPM

2008-01-22T15:35:00.000+05:30

for that u need to query the rpm name installed in your system

1) rpm -q softwarename.It will show u installed version of the rpm.
e.g. rpm -q yahoo.

2)rpm -e rpmname (what name u get from querying)

################
################

you have done….!!!!!

The Linux from a Begineers point of View

2007-12-30T17:49:00.000+05:30

As a begineer if one wants to learn linux then Fedora 8 is the one which i recommend most. It has many magical features. Just chekc it out once ill give 4 out of 5 to this.
now fedora 7 it deserve jst 3 out of 5 coz of the complications.

Ubantuu 7 : 4 out of 5 bt from a programmers point of view it doesnt deserve this much.

rest i never tried bt soon ill give more..... Njoy

How to Mount NTFS partitions ?

2007-12-14T02:00:00.000+05:30

To mount NTFS partitation use "ntfs-3g" in place of "vfat", remember that on NTFS if Windows is installed and currently in hibernate mode then linux will failed to mount the partition, infact whenever windows is in hibernation mode on NTFS partition , Linux Always failed to mount.

"Knowledge Belongs to World, Encourage Opensource"

How to install More than one GCC compilers on your linux?

2007-12-13T04:09:00.000+05:30

–>say in my example.I am using redhat9 linux and it is having gcc-3.2.2 installed.
now I want to install gcc-4.0.2 as the new compiler.but with the same time gcc-3.2.2 should not get overwritten.

1)get the source of the compiler u want to install say gcc-4.0.2

2)copy that in /root folder
so now u have folder called gcc-4.0.2 inside the /root.

3)make directories inside the /root as follows:
–>mkdir gcc-build–>cd gcc-build–>mkdir gcc4–>cd

4)now go inside gcc-build directory–>cd gcc-build

5)configure gcc with following command
–>sh ../gcc-4.0.2/configure –prefix=/opt/gcc-4.0.2

6)after that make with following command
–>make

7)now as we have done make process we need to do make install so follow following command
–>make DESTDIR=/root/gcc-build/gcc4 install
above command will install gcc in folder called “gcc4″ that we have made in step 3.
now with above set of command u are done with installing the gcc4.0.2 in your system.
But the question is how would u know that new gcc is installed or not??for that ..

8)goto terminal follow following command
–>cd–>gcc -v #this will show you default version of the compiler installed in your system–>gcc-build/gcc4/opt/gcc4.0.2/bin/gcc -v #this will show u the newly installed compiler on your system

Here I have taken example of gcc4.0.2 but u can have other version instead according to your need.And follow the same procedure for installing more than one gcc.
Post your experience with the same..

Regards,
Tushar .