Changing login screen in Ubuntu

One of my friends had a new theme installed in his Ubuntu system but the login screen was that of the default theme. He thought changing the login screen is a big task. It is very simple as follows

The desktop appearance properties window should be linked or copied to login window.

sudo cp /usr/share/applications/gnome-appearance-properties.desktop /usr/share/gdm/autostart/LoginWindow.

Instead of copying you can give links too.

When the login screen is prompted again, the background appearance changing window will also be popped out and with that you can change your login screen to your theme login screen. If there is no separate login screen you can use your desktop screen itself. Now you can see your login screen matches your newly installed theme.

After logging in do unlink so that the background changing window wont prompt again along with the login screen.

sudo unlink /usr/share/gdm/autostart/LoginWindow/gnome-appearance-properties.desktop

Dialup in Linux-For Newbies

For new Linux users configuring their system for dialup net connection seems tougher if they are having the built in modem. The main reason is most software modems are based on Windows and they dont get detected in Linux. For that, corresponding drivers should be installed. googling will help in finding the corresponding drivers.

For example if your modem in WinXP is Modem-Agere Systems PCI Soft Modem(COM3), the driver agrsm can be used.

Before installing the driver be sure that the kernel headers are installed. The kernel names will be like
linux-headers-2.6.18-4
linux-headers-2.6.18-4-686
kernel-kbuild-2.6-18

The agrsm tar should downloaded from the site. Do the following steps
tar xzvf agrsm-***.tar.gz
cd agrsm
make
make install
The above steps will complete the driver installation. Then load the drivers
1) Next load the drivers
modprobe agrmodem
modprobe agrserial
which should announce creation of /dev/ttyAGS3

2) It is convient to create symbolic links, which dialer utilities will follow,to the real port /dev/ttyAGS3 .
ln -s /dev/ttyAGS3 /dev/ttySAGR
ln -s /dev/ttyAGS3 /dev/modem
Check with:
ls -l /dev/ttyAGS3 /dev/ttySAGR /dev/modem
whose output should include:
/dev/modem --> /dev/ttyAGS3
/dev/ttySAGR --> /dev/ttyAGS3

3) The first critical functial test is:
wvdialconf /etc/wvdial.conf
which searches through potential ports for modem responses.
A success will end with a section like:
--------
ttySAGR<*1>: Modem Identifier: ATI -- Agere SoftModem Version 2.1.40
ttySAGR<*1>: Speed 4800: AT -- OK
ttySAGR<*1>: Speed 9600: AT -- OK
ttySAGR<*1>: Speed 19200: AT -- OK
ttySAGR<*1>: Speed 38400: AT -- OK
ttySAGR<*1>: Speed 57600: AT -- OK
ttySAGR<*1>: Speed 115200: AT -- OK
ttySAGR<*1>: Max speed is 115200; that should be safe.
ttySAGR<*1>: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 -- OK

Found a modem on /dev/ttySAGR.
Modem configuration written to /etc/wvdial.conf.
ttySAGR: Speed 115200; init "ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0"

Dialout Procedure
First edit in your dialout information with:

emacs /etc/wvdial.conf

In the sample below, the lines beginning with are informative, not essential.
The line order is not important.

[Dialer defaults]
# Lines begining with # are comments.
# wvdial will look for this file at /etc/wvdial.conf
# or /home/LoginName/.wvdial.rc
Baud = 115200
Modem = /dev/ttySAGR3
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
# Lack of dialtone acquisition can be due to low line voltage
# Try inserting a "dial without waiting": X3
# Init2 = ATQ0 V1 E1 S0=0 X3 &C1 &D2 +FCLASS=0
# In case of connection instabilities, specify a lower frequency:
# Init2 = ATQ0 V1 E1 S0=0 X3 &C1 &D2 +MS=34

## Outside the USA, a country setting may be needed
# Init3 = AT+CGI=hexadecimal_country_code

ISDN = 0
Modem Type = Analog Modem
Phone = Dialout_phone_number
# if going through a switch board, a perhaps necessary pause can produced with a comma:
# Phone = 1,Dialout_phone_number
Username = LoginName
# if Internet Provider is MSN.net, use under Linux: MSN/LoginName
Password = YourPassWord

## If CONNECT is achieved but browsing fails, try activating the following line
# Auto DNS = yes
## To make a logfile wvdial.out
# wvdial 2>&1 | tee wvdial.out
# # For some Internet providers, the following line is necessary
# Stupid Mode = yes
## for other wvdial options, do "man wvdial" or see the documentation in
## /usr/share/doc/wvdial/
## End wvdial.conf

The above procedure will work if you have installed wvdialconf wvstreams and other required packages.
Ok next time meet me through linux;-)

Disabling User Accounts in Linux

In linux the users can be disabled from accessing their shells temporarily by one of these methods

1.The linux store the encrypted passwords of the users in /etc/shadow file.
By replacing the encrypted password (second field) with * or !, the user cannot login.

2.By using the passwd command the super user can lock the account
passwd username -l
This will add a "!" infront of the encrypted password in /etc/shadow file
To unlock the account,
passwd username -u can be used.
This will remove the "!". This can be done manually too

3.By using chpass command the default shell can be changed to /sbin/nologin
chpass -s /sbin/nologin {username}

finally my prob solved..!!!

In my box i installed OpenSolaris in one hard disk(hd0) and the windows in in another disk(hd1)..
I found difficult in accessing both operating systems from the same grub..Finally i found a solution for this using the grub function map( )
grub> map (hd0,hd1)
grub> map (hd1,hd0)
The map option makes virtual swap between the disks and both the hd0 and hd1 appears virtually as the first disk. Now i can easily enter my windows from the grub without changing the disk every time as i did before..Now i can work in unix environment and see films in windowsXP(what else can we do with windows:-)) without much efforts..meet you with my next "Drop"..bye

FOSS tools-makes programming simple..!!!

Last week i got an opportunity to attend a seminar on FOSS debugging tools by Mr.AnanthShrinivas, an alumnus of our college working in Sun Microsystems.The session was very informative and he showed the demonstration on various debugging tools like GDB-the GNU project debugger, Valgrind, ltrace, mtrace..All the tools are cool to work with. I worked with GDB before the session when my friend introduced it.This session added extra ideas about GDB..The valgrid demonstration was interesting as it pointed errors with memory management in the program with error line numbers.very cool tool..Next i attended a seminar on DBMS and Internet programming tools by Mr.Senthilkumaran,SpikeSource India Limited..He covered various FOSS DBMS tools like MySQL,PostgresSQL,small foot-print databases like SQLite and some informations on the products of SpikeSource..These sessions introduced some interesting tools and i need to work more on it..