mtr(My Trace Route) is a nice network diagnostic tool combines the functionality of the ‘traceroute’ and ‘ping’ programs and can see even the packet  in the network. It comes along with default installtion if ubuntu. To know more type man mtr or follow here . Typical example if usage is below.
Syntax::

 mtr <IP> -n

Below shows the trace to an IP with mtr tool

To install sox

$ sudo apt-get install sox

sox supported formats are

AUDIO FILE FORMATS: 8svx aif aifc aiff aiffc al amb au avi avr caf cdda cdr cvs cvsd dat dvms f4 f8 fap ffmpeg flac fssd gsm hcom htk ima ircam la lpc lpc10 lu m4a mat mat4 mat5 maud mp2 mp3 mp4 mpg nist ogg paf prc pvf raw s1 s2 s3 s4 sb sd2 sds sf sl smp snd sndfile sndr sndt sou sox sph sw txw u1 u2 u3 u4 ub ul uw vms voc vorbis vox w64 wav wavpcm wmv wv wve xa xi PLAYLIST FORMATS: m3u pls AUDIO DEVICE DRIVERS: alsa ao oss ossdsp

to get support of all this formats install

$ apt-get install libsox-fmt-all

We can play specified file format using the play command which come along with sox.

Eg:

fping  is a program like ping which uses the Internet Control Message Protocol (ICMP) echo request to determine if a target host is responding.  fping differs from ping in that you can specify any number of targets on the command  line,  or  specify a file containing the lists of targets to ping. Instead of sending to one target until it  times out or replies, fping will send out a ping packet and move on to the next target in a round-robin fashion.
installing command

sudo apt-get install fping

Script:

#!/bin/sh
status=`fping 192.168.1.22 | cut -d ' ' -f 3`
if [ $status != "alive" ]
then
echo 'system is down' //Here use your alert as you like email, sms, voice alert etc
fi

Will check the system with IP 192.168.1.22 alive or not.Put it as a cron job and schedule the time interval to automatically check system status and get the alert…:)

Normally, run as a console program this will allow you to see slow or badly optimized queries as they will stay on the screen for a while. However, if you are hunting for short lived queries, running in the manualrefresh mode with a short refresh time will allow you to catch short lived queries as well.
Installing mtop

sudo apt-get install mtop

Htaccess is a password protection scheme used by Apache Web servers.The web server will ask an authentication to enter if we set a password for it.Here the steps explains how to set an authentication for the web folder.

1. Create a file called .htaccess in your web folder which you want to protect.
2. Open the file .htaccess in your favorite editor.
3. Paste the lines below.

AuthUserFile /var/www/.htpasswd
AuthGroupFile /dev/null
AuthName "Protected files"
AuthType Basic
require user bipin

4. Change the path of .htpasswd in AuthUserFile where you are going to place the .htpasswd file.
5. Change AuthName to from “Protected files” to any name you would like.
6. Change require user to any user name you would like to give (This will be the authentication user name it will ask).
7. issue command htpasswd -c <htpasswd path> <username> for password setting . For me it is htpasswd -c /var/www/.htpasswd bipin
8. Edit httpd.conf file or the web configuration file of apache.It should be like this.

<Directory /var/www/>
   Options Indexes FollowSymLinks MultiViews
  AllowOverride AuthConfig
 #AllowOverride none
  Order allow,deny
  allow from all
</Directory>

Uncomment AllowOverride AuthConfig if it got commented.

Now onwards it will ask an authentication to enter into it.

By the installation of Linux on a Windows installed machine the default loading OS becomes the Linux. If the user want to change the default one we have to edit the boot loader file of linux OS.

The name and disk location of the GRUB configuration file varies from system to system; for example, in Ubuntu, Debian GNU/Linux and openSUSE the file is stored in /boot/grub/menu.lst while Fedora and Gentoo Linux uses /boot/grub/grub.conf. Fedora also provides a symbolic link from /etc/grub.conf to /boot/grub/grub.conf for FHS compatibility reasons and other distros can establish symbolic links to the three locations.

Well we have created a PHP daemon.One major issue with all daemon is that some time it got killed with out any reason.Here we have a solution for monitoring the daemon with a utility called monit.monit is a utility for managing and monitoring, processes, files, directories and devices on a Unix system. Monit conducts automatic maintenance and repair and can execute meaningful causal actions in error situations. E.g. monit can start a process if it does not run, restart a process if it does not respond and stop a process if it uses to much resources. You may use monit to monitor files, directories and devices for changes, such as timestamp changes, checksum changes or size changes.
For doing it install the utility first

sudo apt-get install monit

We have to edit some configuration file to make the monit work.
Edit sudo vim /etc/default/monit

Set startup=1 from 0

Edit sudo vim /etc/monit/monitrc
This is the file where we specify what to monit
Uncomment

set daemon  60 #will check the daemon every 1 minute
set httpd port 2812 and
 use address localhost  # only accept connection from localhost
 allow localhost        # allow localhost to connect to the server and
#specifying the program for monitor
check process php with pidfile "/var/run/process.pid"
start = "/usr/bin/php /var/www/voicealerts/process.php"
stop = "/usr/bin/php /var/www/voicealerts/process.php"

Line 1 starts a process service entry. It contains the keyword check and a descriptive name for he process to monitor, in this case php. Monit also require the process pidfile to be stated.
If you want monit to start, stop or restart the process you must submit a start and stop program.
Line 2-3 defines those programs for this process
Write and quite the file and check the syntax is ok with command

sudo monit -t

start monit deamon by

sudo /etc/init.d/monit start

start the files specified in the monitrc by

sudo monit start all

check the status of our daemon

sudo monit status

This is a sample configuration monitors the PHP daemon process mentioned in the above post.

Audacity is a free digital sound editing application we can import sound format like mp3, wav etc and edit and export to any other sound format.

To install audactiy in ubuntu issue

sudo apt-get install audacity

One of the issue facing with audacity application is that the export to mp3 fromat will not work in the default installation.This is due to the absence of the lame mp3 encoder.

To solve this install it as follows.

sudo apt-get install  lame
sudo apt-get install  lame-extras
sudo apt-get install  lame-dev
sudo apt-get install  liblame0

To install nmap issue

sudo apt-get install nmap

eg:

To check the status of a particular port in the local host we can issue

nmap -p 80 localhost

will give

Starting Nmap 4.53 ( http://insecure.org ) at 2008-04-17 18:58 IST
Interesting ports on localhost (127.0.0.1):
PORT STATE SERVICE
80/tcp open http

if its open.Similarly we can give any host name.

For scanning a network is live or not we can give

nmap -sP -vv 192.168.0.* | grep up

Host 192.168.0.1 appears to be up.
Host 192.168.0.100 appears to be up.
Host 192.168.0.101 appears to be up.
Host 192.168.0.102 appears to be up.
Host 192.168.0.103 appears to be up.
Host 192.168.0.104 appears to be up.
Host 192.168.0.111 appears to be up.
Host 192.168.0.112 appears to be up.
Host 192.168.0.115 appears to be up.
Host 192.168.0.117 appears to be up.
Nmap done: 256 IP addresses (10 hosts up) scanned in 4.630 seconds

will give this if all are up

#!/bin/sh
rm 1.txt
HOST=’213.104.257.88′
PORT=’21′
USER=’bipin’
PASSWD=’bipin’
FILE=’1.txt’
ftp -n $HOST $PORT <<END_SCRIPT
quote USER $USER
quote PASS $PASSWD
cd ftp
bin
get $FILE
quit
END_SCRIPT
exit 0