OpenPeta » Common Errors And Solutions

Ubuntu Tips and Tricks – 1

ANTHONIRAJ — Mon, 25 May 2009 01:18:01 +0000

Installing and Working NS2 [ Network Simulator ] is very difficult in Ubuntu Linux . We need to change lot of configuration files and applying patches . Like this lot of small issues are there in Ubuntu . so we decided to prepare small tips and tricks for those problems. one of my student prepared some tips for the following issues

Procedure to create and login as root from GUI [ Not Recommended for Normal users]
Procedure to install NS2 [ Network Simulator] in ubuntu 8.10
Procedure to install VLC player in Ubuntu 8.10
Procedure to install Real player in Ubuntu 8.10

Solutions are available in PDF file format . Just Click Here to Download the file

Taking a Screenshot From A Daemon/Shell Script/Command Line

admin — Wed, 01 Apr 2009 18:14:00 +0000

Taking a screenshot is very simple in Linux. Just hit the print screen button and we’re presented with a PNG file.But there are situations when we want to take a screenshot from a command line. Perhaps in a shell script, a daemon tool that we use to
monitor the user’s activity. We would like to take a screenshot without the user having to press the print screen button to log a user’s activity. Perhaps to record the on screen activity in response to some suspicious user action.

This is done using the xwd command in combination with other commands.

The following command can be used to take screenshot without the user
having to click on any window:

xwd -root | xwdtopnm | pnmtopng > Screenshot.png

For this command to work you need the following packages:

1. x11-apps
2. netpbm

Raja Sekharan is a freelance web developer who writes web development tutorials on his blog. Prototype Pro.

Connecting Internet Using BSNL EVDO Card or Mobile GPRS in Fedora 9 / 10

admin — Thu, 19 Feb 2009 11:52:00 +0000

http://linuxforadmin.blogspot.com/2008/03/how-to-connect-bsnl-evdo-datacard-in.html

refer this link for configuring BSNL EVDO card in Linux . After configuring Card goto terminal in super user mode

#su
Password :

Use wvdial command for connecting Internet …

#wvdial
–> WvDial: Internet dialer version 1.60
–> Cannot get information for serial port.
–> Initializing modem.
–> Sending: ATZ
ATZ
OK
–> Sending: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
OK
–> Modem initialized.
–> Sending: ATDT#777
–> Waiting for carrier.
ATDT#777
CONNECT
–> Carrier detected. Starting PPP immediately.
–> Starting pppd at Thu Feb 19 15:29:21 2009
–> Pid of pppd: 3989
–> Using interface ppp0
–> pppd: ��[08]`��[08]
–> pppd: ��[08]`��[08]
–> pppd: ��[08]`��[08]
–> pppd: ��[08]`��[08]
–> pppd: ��[08]`��[08]
–> local IP address 10.3.2.53
–> pppd: ��[08]`��[08]
–> remote IP address 10.64.64.64
–> pppd: ��[08]`��[08]
–> primary DNS address 218.248.240.181
–> pppd: ��[08]`��[08]
–> secondary DNS address 218.248.240.180
–> pppd: ��[08]`��[08]

Now Net is connected , even though You cant surf / browse / ping anything in Fedora . You need to configure the
name server . so goto the following file and add this “nameserver 218.248.240.181″

#vi /etc/resolv.conf
nameserver 218.248.240.181

save and exit from the file …. Now You can surf internet using firefox browser ………………..

Joining Video Files Using Mencoder

admin — Fri, 16 Jan 2009 03:07:00 +0000

Mencoder and cat commands are used to join the more than one video files .The video file may be .avi or .mpg. Here the steps for Ubuntu OS

Step 1: Install the mencoder plugin

sudo apt-get install mencoder mplayer

Step 2 : Concatenate the files using cat command

cat file1.avi file2.avi file3.avi > out.avi

Step 3 : Encode the audio and video using mencoder

mencoder -forceidx -oac copy -ovc copy out.avi -o final.avi

Now the final.avi has full movie……

stdio.h: No such file or directory

admin — Fri, 25 Jul 2008 01:59:00 +0000

sam.c:1:18: error: stdio.h: No such file or directory
sam.c: In function ‘main’:
sam.c:4: warning: incompatible implicit declaration of built-in function ‘printf’

This error occurs when you try to execute c program in Ubuntu . because of libc and libstdc++ package not installed in your Ubuntu.

so first install the libc package using following command

sudo apt-get install build-essential

Now run your C program …..

Netbeans Display Problem in Ubuntu

admin — Mon, 30 Jun 2008 16:30:00 +0000

Sometimes in Ubuntu or other linux OS , when you try to install Netbeans, you will get only blank netbeans window. this problem occurs due to AWT_Toolkit error.

Solution

1. Goto terminal
# vim /etc/profile
Add the following Sysntax

export AWT_TOOLKIT=MToolkit

Save the file , now run or install netbeans …

Netbeans 6.0 Installation Problem in Fedora 8

admin — Thu, 03 Apr 2008 13:07:00 +0000

I Installed manually jdk 1.6.0 in my /usr/local/jdk1.6.0 path .
When i try to install netbeans 6.0, i got some errors.
Error details
[root@antony]# ./netbeans-6.0-linux.sh
Configuring the installer…
Searching for JVM on the system…
Java SE Development Kit (JDK) was not found on this computer
JDK 6 or JDK 5 is required for installing the NetBeans IDE. Make sure that the JDK is properly installed and run installer again.
You can specify valid JDK location using –javahome installer argument.

To download the JDK, visit http://java.sun.com/javase/downloads

So tried with –javahome options but again i got some errors

[root@antony]# ./netbeans-6.0-linux.sh –javahome “/usr/local/jdk1.6.0/”
Configuring the installer…
Searching for JVM on the system…
Extracting installation data…
Running the installer wizard…
java: xcb_xlib.c:50: xcb_xlib_unlock: Assertion `c->xlib.lock’ failed.
./netbeans-6.0-linux.sh: line 1360: 8340 Aborted /usr/local/jdk1.6.0/bin/java -Xmx256m -Xms64m -Djava.io.tmpdir=/tmp -classpath /tmp/.nbi-4044410.tmp/bundle.jar org.netbeans.installer.Installer

Finally i found solution for this probelm,

Step 1:
goto jre path in java installation directory
[root@antony]# cd /usr/local/jdk1.6.0/jre/lib/i386/
Step 2 :
execute the following two commands
[root@antony i386]# sed -i ‘s/XINERAMA/FAKEEXTN/g’ xawt/libmawt.so
[root@antony i386]# sed -i ‘s/XINERAMA/FAKEEXTN/g’ headless/libmawt.so

Step 3 :
Now execute netbeans with LAX_VM option
[root@antony i386]# ./netbeans-6.0-linux.sh LAX_VM /usr/local/jdk1.6.0/jre/bin/java

Thats all …

Error Handling – Bad Interpreter : No such file or directory

admin — Fri, 21 Mar 2008 00:09:00 +0000

Error : /bin/sh^M Bad Interpreter : No such file or directory

This is one common problem when you try to execute shell script in Linux machine.
When i install Octave in my Ubuntu Gutsy Gibbon i got this error.finally i changed all confiuration shell scripts into unix support format
using dos2unix command . (Install sysutils package for dos2unix in Ubuntu using synaptic package manager).

File name : configure.in (This is in dos support format)

Now i am going to chang this file to unix support format

# dos2unix configure.sh

then this script will work ………….