Difference Between GZIP and TAR

In Short:
1. Gzip is a compression tool used to reduce the size of a file
2. Tar is an archiver used to to combine multiple files into one
3. Gzip and Tar are usually used in tandem to create Tarballs that are compressed significantly
4. Extracting an individual file can take a lot longer with zipped tarballs than with other formats

Brief:-

GZIP vs TAR
The .tar.gz extension is a very popular one when downloading files especially in non Windows operating systems. But unlike most extensions, this is not meant to identify a single program that would be used to open this file; it points to two. Tar is a file format but is also the name of the program that produces the file. Tar is an archiver, meaning it would archive multiple files into a single file but without compression. Gzip which handles the .gz extension is the compression tool that is used to reduce the disk space used by the file.

Most Windows users are used to having a single program compress and archive the files. Some of the programs that do this are Winrar, 7zip, and Winzip. But this is not the case in the UNIX and Linux environments where archiving and compressing are two different operations altogether. Tarball is the name used to identify any collection of files that have been archived into a single file by the Tar application whether it is compressed or not. Although Gzip is the most common compression tool that is used with tarballs, it is not the only one. There is also another compression tool called Bzip2 that could compress the file further but would take a lot longer.

There are advantages and disadvantages in creating a zipped tarball compared to the standard applications that does both. A zipped tarball could have dramatically reduced filesize the compression tool is not compressing the files individually but treating the whole tarball as one big file. This is even more apparent when dealing with semi compressed files like GIF and JPG files.

The disadvantage of using this format is that you would be unable to extract a single file. Since the entire archive is compressed as a whole, you would also need to uncompress the whole archive before extracting a single file. Extracting a single file from a large zipped tarball could take significantly longer compared to extracting a single file from the same files compressed and archived by a different tool like Winrar or Winzip.

Kickstart Installation in Linux

Many system administrators would prefer to use an automated installation method to install Red Hat Enterprise Linux on their machines. To answer this need, Red Hat created the kickstart installation method. Using kickstart, a system administrator can create a single file containing the answers to all the questions that would normally be asked during a typical installation.
Kickstart files can be kept on a single server system and read by individual computers during the installation. This installation method can support the use of a single kickstart file to install Red Hat Enterprise Linux on multiple machines, making it ideal for network and system administrators.
Kickstart provides a way for users to automate a Red Hat Enterprise Linux installation.

To begin a kickstart installation, you must boot the system from boot media you have made or the Red Hat Enterprise Linux CD-ROM #1, and enter a special boot command at the boot prompt. The installation program looks for a kickstart file if the ks command line argument is passed to the kernel.

CD-ROM #1 and Diskette
The linux ks=floppy command also works if the ks.cfg file is located on a vfat or ext2 file system on a diskette and you boot from the Red Hat Enterprise Linux CD-ROM #1.

An alternate boot command is to boot off the Red Hat Enterprise Linux CD-ROM #1 and have the kickstart file on a vfat or ext2 file system on a diskette. To do so, enter the following command at the boot: prompt:

linux ks=hd:fd0:/ks.cfg
With Driver Disk
If you need to use a driver disk with kickstart, specify the dd option as well. For example, to boot off a boot diskette and use a driver disk, enter the following command at the boot: prompt:

linux ks=floppy dd
Boot CD-ROM
If the kickstart file is on a boot CD-ROM as described in Section 1.8.1 Creating Kickstart Boot Media, insert the CD-ROM into the system, boot the system, and enter the following command at the boot: prompt

Other options to start a kickstart installation are as follows:

ks=nfs::/The installation program looks for the kickstart file on the NFS server , as file . The installation program uses DHCP to configure the Ethernet card. For example, if your NFS server is server.example.com and the kickstart file is in the NFS share /mydir/ks.cfg, the correct boot command would be ks=nfs:server.example.com:/mydir/ks.cfg.

ks=http:///The installation program looks for the kickstart file on the HTTP server , as file . The installation program uses DHCP to configure the Ethernet card. For example, if your HTTP server is server.example.com and the kickstart file is in the HTTP directory /mydir/ks.cfg, the correct boot command would be ks=http://server.example.com/mydir/ks.cfg.

ks=floppy
The installation program looks for the file ks.cfg on a vfat or ext2 file system on the diskette in /dev/fd0.

ks=floppy:/The installation program looks for the kickstart file on the diskette in /dev/fd0, as file .

ks=hd::/
The installation program mounts the file system on (which must be vfat or ext2), and look for the kickstart configuration file as in that file system (for example, ks=hd:sda3:/mydir/ks.cfg).

ks=file:/
The installation program tries to read the file from the file system; no mounts are done. This is normally used if the kickstart file is already on the initrd image.

ks=cdrom:/The installation program looks for the kickstart file on CD-ROM, as file .

ks
If ks is used alone, the installation program configures the Ethernet card to use DHCP. The kickstart file is read from the “bootServer” from the DHCP response as if it is an NFS server sharing the kickstart file. By default, the bootServer is the same as the DHCP server. The name of the kickstart file is one of the following:

If DHCP is specified and the boot file begins with a /, the boot file provided by DHCP is looked for on the NFS server.

If DHCP is specified and the boot file begins with something other then a /, the boot file provided by DHCP is looked for in the /kickstart directory on the NFS server.

If DHCP did not specify a boot file, then the installation program tries to read the file /kickstart/1.2.3.4-kickstart, where 1.2.3.4 is the numeric IP address of the machine being installed.

ksdevice=
The installation program uses this network device to connect to the network. For example, to start a kickstart installation with the kickstart file on an NFS server that is connected to the system through the eth1 device, use the command ks=nfs::/ ksdevice=eth1 at the boot: prompt.

How to Install TeamViewer on CentOS

How to Install TeamViewer on CentOS

Steps to Install Team Viewer 5 (all version) on Linux ( Fedora, RHEL, CentOS) Red Hat Enterprise Linux.

1) Download Team Viewer 5. Execute Following Command on Linux Terminal.

wget -c http://www.teamviewer.com/download/teamviewer_linux.rpm

Or You can also click on above link to Download using your Browser.

2) Now It’s Time to Install Team Viewer 5 on Linux. Execute Following Command as root.

rpm -ivh teamviewer_linux.rpm

3) Once Team Viewer Get Installed. Make sure you are switch to Normal User. Because New Team Viewer cannot be run as root.

From GUI :- Click on Applications -> Internet -> TeamViewer

Linux Boot Sequences

Linux Boot Sequences
Mostly Linux boot sequence is parted in 6 Stages
1. Bios- Basic Input/Output
2. MBR- Master Boot Record (keeps Grub information)
3. GRUB/LILO- GRUB(Grand Unified Bootloader) or LILO- Linux Loader(The old technique)
4. Kernel
5. Init- keeps all init processes.
6. Runlevel- starts all init processes.

Linux Commands Documentation

Linux Commands Documentation

Starting with A

# a2ps- Formats files for printing on a PostScript printer
# AMSTeX- formatting documents with TeX, AMS version
# AMSLaTeX- AMS version of LaTeX
# at- allows you to run programs at a later date
# awk- pattern scanning and string manipulation language, developed by GNU. See also mawk, a POSIX implementation of awk

Starting with B

# bash- The bourne again shell, one of the two basic ways you interact with the computer, the other is the tcsh shell
# bc- an arbitrary precision calculator. If you want a calculator for X-windows try xcalc
# bibtool- BibTeX file manipulation tool
# bison- the YACC-compatible Parser Generator
# bzip2- a file compressor

Starting with C

# cdrecord- record audio and data Compact Discs. There is also a graphical program called xcdroast
# chmod- to change permissions of files
# chown- to change ownership of files
# chktex- finds LaTeX errors
# cjpeg- compress an image file to a JPEG file
# clisp- common Lisp language interpreter
# cmp- compares two files.
# convert- converts between different formats of image files
# cpio- copy files to and from archives
# cp- to copy one file into another
# cpp- the GNU C preprocessor
# cron- to run programs periodically (as opposed to at, which run them just once); this link contains the format of the control file.
# csh- the C shell

Starting with D

# date- shows (and sets up, for the super user) the system date
# dc- an arbitrary precision calculator; see also bc
# ddd- Data Display Debugger, the debugger for gcc (GNU C compiler)
# diff- shows the differences bewteen two files; see tkdiff for a graphical program that does a similar job and zdiff to look at differences between compressed files
# dqs- a batch queueing system that allows to queue jobs (programs) in different machines to be run according to the load of the machines. You can check also reference guide. See also queue
# dvips- converts files from TeX DVI format to PostScript

Starting with E

# elm- a program to read/send email for UNIX:
# emacs- the GNU editor where all started… There is a similar program for X-windows (graphical interface) called xemacs
# expect- a toolf fo rautomating interactive applications such as telnet, ftp, rlogin, etc (the Frequently Asked Question file)
# egrep- searches one or more input files for lines containing a match to a specified pattern

Starting with F

# flex- fast lexical analyzer generator, or a tool for generating programs that performs patter-matching on tex.
# ftp- the File Transfer Program, that allows the transfer of file between computers connected to the Internet (or some sort of network)
# find- searchs for files in a directory
# free- show how much memory is being used and how much is free in the system
# fromdos- converts a file from DOS format to UN*X format; the reverse process is done with todos
# fvwm95- a X-windows manager that will make your computer look like Windows’95: here you have an example of a configuration file

Starting with G

# g++ – the GNU C++ compiler (it is also the GNU C compiler)
# gimp- an image manipulation and paint program
# g77- the GNU Fortran compiler
# gawk-same as awk above
# gcc- the GNU C compiler
# giftrans- allows to put transparent or background colors on GIF files
# gmp- the GNU multiple precision arithmetic library, to write C programs with arbitrary precision
# grep- same as egrep above
# gdb- Data Display Debugger, same as ddd above
# gs- a PostScript and PDF language interpreter and previewer
# gsl- the GNU Scientific Library, for writting programs in C
# gv- a previewer for PostScript and PDF files
# gzip- compress files

Starting with H

# hcc- a brief reference to C/C++ compiler for LAM (parallel compiling)
# head- show the beginning (head) of a file
# hexdump- gives the hexademic format of files in the computer
# host- a program to find addresses (and other data) of computers connected to the Internet

Starting with I

# indent- a program that makes C code easier to read and converts from one style of writing C (eg. GNU, Kernighan & Ritchie, Berkeley) to another
# Imagemagick- a program to display and manipulate image files
# imake- the make command for X11 (manual page formatted on html)
ispell, a spell checker
# imp- a program to read your mail via a web browser (like Netscape)

Starting with K

# kill- stops processes running in a computer
# killall- kills processes by name

Starting with I

# latex- to format documents, especially mathematics; quite complete user’s guide. If you want to find a particular symbol you can check this table of LaTeX symbols
# latex2html- converts from LaTeX to HTML (web based files)
# less- a command to look a files (a PAGER, in UN*x language)
# lpq- the command to look at the printer queue
# lpr- the command to print
# ls- to list contents and information of files and directories
# lynx- a text-based browser, useful for example for pages with too many graphics or bad Java scripts (or if you want fast browsing)

Starting with M

# magma- a Computer Algebra system for solving problems in algebra, number theory, geometry and combinatorics (works only in prime). For the full documentation you can start with link
# mailx- the basic UNIX command to send/read mail
# make- a tool to generate execuatable files from a program’s source files
# man- the program to look at manual (help) pages of Linux/UN*X commands
# mathematica- a commercial program for mathematical computations
# maple- another commercial program for doing mathematical computations
# mawk- an implementation of awk (pattern scanning and string manipulation language) that tries to follow the POSIX standard. See also awk, the GNU implementation of awk
# mc- the Midnight Commander, a directory/file manager for UN*X operating systems
# mkisofs- program used to create file systems to later write them on CDs
# montage- creates a composite image by combining several separate images
# more- a program that allows you to look at files (like less, but no so powerful)
# mtools- a set of programs that allows you to handle DOS files and directories, in particular floppy disks. The most common commands are the following:
# mcd- to change directories
# mcopy- to copy between DOS and Linux files
# mdel- to delete DOS files
# mdir- to make DOS directories
# mdu- to check the usage of DOS files in a floppy/file system
# mformat- to format a floppy to be used as DOS floppy later
# mv- renames files

Starting with N
# ncftp- a powerful interface for using ftp (File Transfer Protocol)
# newalias- install new elm aliases
# nice- makes processes to run on low priority so the system can do more impotant tasks. If the process is already running you can use the command renice
# nsloopup- a program to find addresses (and other data) of machines connected to the Internet. Note: better use the program “host” as this program might disappear in the future

Starting with P

# pari- software package for computer-aided number theory, consisting of a C library (to write your own programs) and an interactive calculator called gp
# pdflatex- produces PDF output (instead of standard dvi file) from a LaTeX file
# pdftex- produces PDF output (instead of standard dvi file) from a TeX file. You can check a sample document here
# pdftops- converts PDF (Portable Document Format) files to PostScript so they can be printed.
# pftp- the same as ftp but called in a “passive” way, good for example when two computers are connecting with firewall between them.
# pico- a simple editor that comes with the “pine” package
# pilot- a file browser in the style of “pine”
# pine- a popular program to read email. The documentation for the latest version (“pine 4”) is available: pine4. Check also elm, another popular email program.
# pmake- a version of make, that is, a tool to generate execuatable files from a program’s source files
# ps2pdf- converts PS files to PDF files
# psselect- select pages from a PS file (for example, to print only certain number of pages)
# psbook- arranges pages in a PS file so the print out looks like a book

Starting with Q

# queue- allows to queue jobs (programs) in different machines to be run according to the load of the machines. See also dqs
# quota- displays users’ disk usage and limits

Starting with R

# rcs- Revision Control System, a program that allows you to keep different versions of a file/document in a single “control” file; good, for example, when you are editing a file very frequently and do not want to have too many files with similar names
# renice- to change priority of running processes, so they can be slowed down allowing the system to work faster on more important tasks. You can look at the information about nice command that allows you to start a process with low priority.
# rm- deletes files
# rsh- remote shell, allows you to login or execute programs in a remote computer

Starting with S

# scanimage- a simple command-line (no graphical interface) program to interact with a scanner. See also
# xscanimage- the command with graphical interface
# sendfile- a program to send files via Internet
# setterm- changes the properties of the terminal (“screen”), like number of lines/rows, automatic line wrap, etc
# shar- creates shell archives (shar files); these are packed files that can be unpacked later in a simple way bu executing a command. The packed files can be send by email
# sleep- delays for a specified amount of time (it does nothing for some time, hence the name of the program)
# sort- sorts lines in a text file
# spell- a UN*X spell emulator, simpler and less powerful than ispell
# split- splits a file into smaller files, good for example to send small files by email
# ssh- the Secure Shell, allows you to execute commands or login in a remote computer in a secure (crypted) way. It should be prefereed to the rather equivalent, non-secure, rsh

Starting with T
# tail- shows the end (tail) of a file
# tar- a program to create and manipulate archives (“tar files”) which are actually collections of many other files
# tcsh- a very popular shell (that is, the basic program that allows you to execute commands, and it is the one you run after login in the system). An example of a configuration file can be found here. The other popular shell is bash
# tee- reads from standard input (basically keyboard or a file) and writes to standard output (screen) and files; good if you want to write something to a file and see what is written at the same time
# telnet- allows you to log on in a computer conneted to the Internet or a local network
# telnet-ssl- like telnet above but with crypted communication, to increase security
TeX, to typeset mathematical documents; this is the manual page of the command “tex”; there is lot of documentation in the Internet
# time- runs programs and tells how much time (real time and computer usage) they take
# tkdesk- a Graphical File and Desktop Manager for X-windows
# tkdiff- this program displays in a nice, graphical way, the differences between two files
# tkdvi- a dvi previewer based on tcl/tk, adds some features to the standard dvi previewers like xdvi
# todos- converts a file from UN*X format to DOS format; the reverse process is done with fromdos
# top- shows processes running, displaying the most CPU-intensive tasks, and allows renice and kill them
# touch- allows to change the timestamps of files
# traceroute- finds the route that packets take between your computer and another computer connected to the Internet or a local network. It might not work if your computer is behind a firewall that does not allow ping (for security reasons)
# transfig- creates a make file to translate figures in FIG code to LaTeX
# tree- lists all the files in a directory in a tree-like format

Starting with U

# uname- gives information about the machine you are working on, like hardaware type, name, processor, operating system.
# uname- gives information about the machine you are working on, like hardaware type, name, processor, operating system…
# untex- removes LaTeX commands from a file
# unzip- extracts or lists the files in a “qip” archive (a type of file that has many files within it)
# uuencode- puts a binary file in an encoded format so it can be sent over email as a simple text file; the reverse process is done with uudecode. Nowadays most mail programs can do similar things via MIME without need for the user to do any extra processing
# untex- removes LaTeX commands from a file
# unzip- extracts or lists the files in a “qip” archive (a type of file that has many files within it)
# uuencode- puts a binary file in an encoded format so it can be sent over email as a simple text file; the reverse process is done with uudecode. Nowadays most mail programs can do similar things via MIME without need for the user to do any extra processing

Starting with V

# vacation- returns a message to senders of an email telling them that you are currently not reading your mail (“on vacation”)
# vi- the classical (and for some people obsure) UN*X editor; if you want a more advanced help you can check this document. Other editors are emacs, pico and xemacs
# vlock- a program to lock one or more sessions on the Linux console

Starting with W

# w- shows who is logged in a computer and what they are doing
# wall- writes a message to all users logged on in a computer
# wc- computes the number of bytes, words and lines in files
# wdiff- displays word differences between text files
# wget- a command to get files from the World Wide Web without using a browser (that is, without netscape, lynx, etc, just a plain command)
# whiptail- display graphical boxes from scripts
# workman- a graphical program to play audio compact discs

Starting with X

# xcal- calendar with alarms and a notebook for X-windows
# xcalc- a scientific calculator for X-windows. See also bc, an arbitrary precision calculator program
# xcdroast- a graphical program to write CDs. See also the more basic, command-line program cdrecord
# xclock- a digital/analog clock for X-windows
# xcolors- displays all the X-windows colors names
# xcolorsel- displays all the X-windows colors names in many formats
# xemacs- a version of emacs for X-windows. You can also access two documentation files in PDF format: the new users’ guide and the more advanced users’ guide
# xfig- a tool to create figures under X-windows (that can be later included in LaTeX files, for example). You can also access the same documentation in a fancier format (frames)
# xfontsel- a program to help you to select fonts for X-windows
# xfreecd- a X-windows program that looks like the frontpanel of a CD player and, as you might expect, plays audio CDs
# xhost- this program is used to add/delete hosts/users names authorised to display windows in your computer
# xlock- program to lock your X-windows session
# xmake- another make utility; check also imake and make
# xman- displays manual pages in a windows environment
# xmcpustate- shows usage of CPU
# xpaint- a graphics program to draw pictures under X-windows; you can save the files in many different formats (including gif and jpeg)
# xpdf- a program to display PDF files; see also gv
# xscanimage- a graphics-based command to use a scanner; see scanimage for a non-graphics command.
# xset- sets preferences for X-windows sessions
# xsysinfo- displays technical information about memory, CPU and other stuff in your machine
# xterm- the “basic” X-windows programs, like a shell, from which you can call any other program
# xxgdb- Data Display Debugger in for X-windows

Starting with Y

# yppasswd- the basic command to change your password in our system (or any system running NIS)
# ytree- a basic file manager that displays the files in a directory in a tree-like form. See also the Midnight Commander

Starting with Z

# zcat- allows you to look at a compressed file
# zdiff- shows differences between two compressed files; see also diff for looking at differences between two “regular” files and tkdiff for a nice graphical program that shows differencese between two “regular” files
# zip- creates ZIP archives, that is files that contain other files inside; see also tar and cpio, two programs that create archives

Note- Welcome all emails/calls from any readers with suggestions, new comments, & corrections at [email protected]