How to install/configure skype in debian based linux?

skype:

 is a VoIP based software application which is mainly used for peer to peer phone/video call, instant messaging over internet connection in free of cost^*.  To use this one should have a valid user account with skype.  Now, skype have features like file transfer,  video conferencing also.

free of cost^*  - Only between skype accounts,  yes you can call/sms any landline/mobile phone... but with applicable call charges :(.

1. Download the latest linux version of skype from here.  Select your exact distribution like debian, Opensuse, ubuntu etc..

2. Install the downloaded package using your package manager.  I am using BOSS GNU/Linux 4.0 and it is a debian based one.  So, the following steps regarding installation is applicable to only to the debian based linux  distributions like ubuntu, BOSS GNU/Linux, linuxmint, knoppix etc.

GUI way:
Right click the downloaded skype-xy-z.deb package -> Open with gdebi package installer -> Install

Command line way:
$dpkg -i fullpath-to-downloaded-directory/skype-xy-z.deb

Once installed, as per your distribution's application classification skype menu will be placed either below internet or sound & video.  In BOSS GNU/Linux it will be placed under Internet.

3. If you have skype user account already then just use it.  If not create your user account by "Do not have user account.? create " link from the Skype GUI application.

GUI -> Graphical User Interface
BOSS -> Bharat Operating system solutions
GNU -> GNU's Not Unix
VoIP - Voice over IP(Internet Protocal)

What is cron,crontab & how to use it?

Cron :
is a daemon process which checks the crontab every minute for checking is there any scheduled task to execute. After this checking it goes to sleep and waits for the next minute to wokeup and check the crontab. The cron daemon is one of the bootup process which starts running from the bootup of the system. If you want to check the cron daemon process, issue the following command in terminal

$ps -e | grep cron

Crontab(le) :
is a file which has the entries for scheduled tasks. The entries follows the following syntax.
M H DOM MOY DOW Task(command)
Where,
M -> Minute entry. Value range (0-59)
H -> Hour entry Value range (0-23)
DOM -> Day of Month Value range (1-31)
MOY -> Month of the Year Value range (1-12)
DOW -> Day of week Value range (0-6) where 0-Sunday, 1-Monday, ....

Example entry:1

Min Hour DOM MOY DOW Task

*   *    *   *   *   date  >> /tmp/every_minute.txt 

* <- means 'for all' The above entry will works on every minute and just appends the output of the command 'date' into the file '/tmp/every_minute.txt'. By opening the every_minute file in gedit you can see the output on every minute. If you want any other task to automate in the backend or chage the time when it needs to run configure the task entry as your need. Example entry:2
Min Hour DOM MOY DOW Task
30 22 * * * rm -r /tmp/*

The above entry will run everyday night 10.30(22.30) and removes everything from the /tmp/ Directory.

So how edit crontab:
In terminal type the following command
$crontab -e

Now the crontab file will opens in your default terminal editor(Mostly vi or vim). Now just add the Example 1 at the bottom of the file then save and exit.
Now open the /tmp/every_minute.txt file you can see it is updated each minute with the output of the date command.

For more information about cron, crontab
$man cron

$man 5 crontab


Location of files related to Cron :
Files in /var/spool/cron, /var/spool/anacron
Files in /etc/cron* ex. /etc/cront.d/, /etc/cront.weekly/
File /etc/crontab


Details Based on:
BOSS GNU/Linux (And most of the debian derived linux)

A simple way to setup a Centralised log Server in Linux

In Linux using UDP, or TCP we can send the logs of various machine into a single machine(Centralised log server).
We need to Configure the machines
1. Server machine - A centralised log server where all the logs are stored.
2. Client machine - which sends logs to the remote machine.

Server side configuration:
1. Open the /etc/rsyslog.conf and find the line "ModLoad" under the 'MODULES' part.

2. If you want to receive the logs by UDP then uncomment the following lines
$ModLoad imudp
$UDPServerRun 514

3. If you want to receive the logs by TCP then uncomment the following lines
#$ModLoad imtcp
#$InputTCPServerRun 514

Note: here 514 is port number

4. Edit the /etc/default/rsyslog file and change the RSYSLOGD_OPTIONS="-r -x -c1"

Note: -r <- Allow remotesystems to log their log entries into the server machine
-x <- Disables DNS lookups on messages received with -r
-c1 or -c2 <- Compatability mode (must not -c3 or -c4 because the compatability mode greater than 2 now allow remot log)

4.1 Restart the rsyslog by $sudo /etc/init.d/rsyslog restart
4.2 Now move to the Client side configuration. After the configuration finished restart the /etc/init.d/rsyslog there also
Now the remote logs are start logged in the log server machine you can veryfy them by $tail /var/log/auth.log. (change user in client machine and see that was logged in the auth.log)
If remote logs not works then do the following steps also in the log-server machine.

5. Open and edit the /etc/default/syslogd file and change the SYSLOGD as follows SYSLOGD="-r -m 0"
Now do the steps 4.1 & 4.2

6. Open and edit /etc/init.d/rsyslog file and change the RSYLOGD_OPTIONS into RSYLOGD_OPTIONS="-r" then do the steps 4.1 & 4.2




Client side configuration:
1. backup the /etc/rsyslog.conf file in anothername say $mv /etc/rsyslog.conf /etc/rsyslog.conf.bak

2. create a new /etc/rsyslog.conf file with the following content.
*.* @Logserver_ipaddress:portnumber


Thats it.. :)
Note: The linux distro am using is BOSS-4.0 (Debian based linux)

How to create a BOSS Linux's installable USB drive using unetbootin?

1. First you need to update with repository
$sudo apt-get update

2. Install the unetbootin package using
$sudo apt-get install unetbootin

3. Now you have a new menu entry in
“Applications → System tools → UnetBootin”



4. Format the USB drive and then copy the BOSS linux's ISO image into it.

5. Open the GUI for creating the Installable USB drive
“Applications → System tools → UnetBootin”
now you will get the following GUI application



6. Select the custom option then browse and select the kernel (vmlinuz), initrd and paste “video=vesa:ywrap,mtrr vga=788” into the Options field




7. Now select Type as USB Drive, Drive as /dev/sdb(n) [n=1,2,3 as no.of usb drives inserted in the system] then click ok.

8. Click Exit. Thats all Installable USB is ready.



9. Now your USB drive has the following files.
1. ISO Image of BOSS linux (Copied manually by us)
2. ldlinux.sys
3. menu.c32
4. syslinux.cfg
5. ubninit
6. ubnkern