How to format Flash/Pen Drive in Linux

Note: I have used my device name and number in examples, you have to change itas your device name and number, otherwise unwanted device data will be wipedout. Put your USB flash drive in one of your computer's free USB ports. After a fewseconds, Linux will automatically recognize it and an icon for it will appear onyour desktop. If pen drive doesn't mounted automatically, login as root and tryto mount it, still it is not mounted there may be a problem with pen drive or itis defective.Finding device: Very very first thing is you should to know...

How to Remove RPM GPG Public Key

Public keys can be erased after importing just like packages. Here's how to remove the CentOS GPG public key: rpm -e <GPG public key> [root@localhost]# rpm -qa gpg-pubkey* gpg-pubkey-e8562897-459f07a4 [root@localhost]# rpm -e gpg-pubkey-e8562897-459f07a4 [root@localhost]# rpm -qa gpg-pubkey* [root@localhost]# If there are duplicates exist: For example, Import the same key two times [root@localhost]# rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5 [root@localhost]#...

How to Import RPM GPG Key

Note: All the commands tested on CentOs 5.x. Your output may be vary depending on distribution and version, so your results may not always look exactly like the listings and figures shown here. Almost all everything works well on RHEL/CentOs/Fedora. Why to check signature of an rpm: The signature confirms that the package was signed by an authorized party and also confirm the integrity and origin of your file. It is extremely important to...

Shell Script to Find Prime Factors of a Number

  In number theory, the prime factors of a positive integer are the prime numbers that divide that integer exactly, without leaving a remainder. The process of finding these numbers is called integer factorization, or prime factorization. The fundamental theorem of arithmetic says that every positive integer has a unique prime factorization. Example: The prime factors of 330 are 2, 3, 5 and 11: 330 = 2 × 3 × 5 × 11 There...

Menu Driven Shell Script - Using Dialog Utility

#!/bin/bash# SCRIPT : menu_dialog.sh# PURPOSE : A menu driven Shell script using dialog utility# which has following options:# Display Today's Date and Time.# Display calendar.# Delete selected file from supplied directory.# List of users currently logged in# Disk Statistics# Exit################################################################################ Checking...

Quicksort Shell Script

Quicksort is a good example of the divide and conquer strategy forsolving problems. In quicksort, we divide the array of items to besorted into two partitions and then call the quicksort procedure recu-rsively to sort the two partitions, ie we divide the problem into twosmaller ones and conquer by solving the smaller onesQuicksort recursive algorithm:1 Select an element (called as pivot) x(p) of x .2 Divide x into two batches x1 and x2 so that all entries of x1 are < x(p) and all entries of x2 are > x(p). all entries of x3 are...

Binarysearch Shell Script

Binary search works by comparing an input value to the middle elementof the array. The comparison determines whether the element equals theinput, less than the input or greater. When the element being comparedto equals the input the search stops and typically returns the posit-ion or number of searches of the element. If the element is not equalto the input and the element at the middle point is greater than theinput being searched, the current middle point becomes the new highpoint and the array is cut in half again and re-tested. If the elementat...

Linear Search Shell Script

#!/bin/bash# SCRIPT : linearsearch.sh# USAGE : linearsearch.sh# PURPOSE: Searches given number in a list.# \\\\ ////# \\ - - //# @ @# ---oOOo-( )-oOOo---# A variation of Here Document permits "commenting out" data block.: <<DATABLOCK In computer science, linear search or sequential search is a methodfor finding a particular value in a list, that consists in checkingevery one of its elements, one at a time and in sequence, until thedesired one is...

Happy New Year Shell Script

Wish You a Happy New Year To All My Friends If you don't know shell color codes, read bellow article first.How to colorize shell scripts#!/bin/bash# SCRIPT: happynewyear.sh# PURPOSE: Prints Happy new year 2011 on screen.# \\\\ ////# \\ - - //# @ @# ---oOOo-( )-oOOo---################################################################################ ...