Java Beginner : Strings and Arrays - Display words that start with a vowel in an user inserted string

/*
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 * and open the template in the editor.
 */
package javaapplication7;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

/**
 *
 * @author Sunshine
 */
public class JavaApplication7 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws IOException {
        // TODO code application logic here
        System.out.println("Please enter some text");
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        String names=br.readLine().toLowerCase();
        StringTokenizer stk=new StringTokenizer(names);
        String vowels="";
        while(stk.hasMoreTokens()){
            String c=stk.nextToken();
            if(c.startsWith("a")||c.startsWith("e")||c.startsWith("i")||c.startsWith("o")||c.startsWith("u"))
                vowels=vowels+" "+c;
        }
        System.out.println(vowels);
        
    }
}

Java Beginner : Strings and Arrays - Display second largest element in the array of names

/*
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 * and open the template in the editor.
 */
package javaapplication6;

/**
 *
 * @author Sunshine
 */
public class JavaApplication6 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
         String[] names = new String[]{"ravi kiran", "aarushi madiratta", "himani jain", "nancy agarwal","manish kapoor","poonam yadav","silko malik"};
        bubblesort(names);
      
       System.out.println("The second largest element in the arraay of names is : "+names[names.length-2].toUpperCase());
      


    }

    public static void bubblesort(String[] text) {
        int j;
        boolean flag = true;
        String temp;

        while (flag) {
            flag = false;
        
        for (int i = 0; i < text.length - 1; i++) {
            if (text[i].compareToIgnoreCase(text[i + 1]) > 0) {
                temp = text[i];
                text[i] = text[i + 1];
                text[i + 1] = temp;
                flag = true;
            }
        }
    }
    }
}
    

Java Beginner : Strings and Arrays - Sort Array of names

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package javaapplication5;

/**
 *
 * @author Sunshine
 */
public class JavaApplication5 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here

        String[] names = new String[]{"ravi kiran", "arushi madiratta", "himani jain", "nancy agarwal","manish kapoor","poonam yadav","silko malik"};
        bubblesort(names);
        for (int i = 0; i < names.length; i++) {
            System.out.println(names[i]);
        }


    }

    public static void bubblesort(String[] text) {
        int j;
        boolean flag = true;
        String temp;

        while (flag) {
            flag = false;
        }
        for (int i = 0; i < text.length - 1; i++) {
            if (text[i].compareToIgnoreCase(text[i + 1]) > 0) {
                temp = text[i];
                text[i] = text[i + 1];
                text[i + 1] = temp;
                flag = true;
            }
        }
    }
}

Java Beginner : Strings and Arrays - Sort a user inserted string

/*
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 * and open the template in the editor.
 */
package javaapplication4;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;

/**
 *
 * @author Sunshine
 */
public class JavaApplication4 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws IOException {
        // TODO code application logic here
        
        System.out.println("Please enter the text");
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String inp = br.readLine().toLowerCase();
        char[] input=inp.toCharArray();
        Arrays.sort(input);
        
            System.out.println(input);
       
        
    }
}

Java Beginner : Strings and Arrays - Count the number of occurrences of each vowel in a string

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package javaapplication2;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 *
 * @author Sunshine
 */
public class JavaApplication2 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws IOException {
        // TODO code application logic here
        System.out.println("Enter some text");
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String input = br.readLine().toLowerCase();
        
        char[] vowel = new char[]{'a', 'e', 'i', 'o', 'u'};
        int[] countVowel = new int[5];
        for (int j = 0; j < input.length(); j++) {
            char c =input.charAt(j);
            if(c=='a')
                countVowel[0]++;
            else if(c=='e')
                countVowel[1]++;
            else if(c=='i')
                countVowel[2]++;
            else if(c=='o')
                countVowel[3]++;
            else if(c=='u')
                countVowel[4]++;
           

        }
         for (int i = 0; i <countVowel.length; i++) {
                System.out.println("Count of vowel " + vowel[i] + "=" + countVowel[i]);
            }
            
        }
    }

Session tracking: URL Encoding Technique in Java Servlets

The structure of the application is like this:

Encode.jsp


<%-- 
    Document   : encode
    Created on : Sep 11, 2012, 12:12:41 PM
    Author     : Sunshine
--%>

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <h1>lets do URL encoding!</h1>
        <c:url value="http://localhost:8080/SimpleCookies/decode.jsp" var="decoderpage"/>
        <a href="<c:out value="${decoderpage}"/>">click here</a>
            
    </body>
</html>

decode.jsp

<%-- 
    Document   : decode
    Created on : Sep 11, 2012, 12:12:53 PM
    Author     : Sunshine
--%>

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <%
        String descriptor;
        if(session.isNew())
            descriptor="This is a new session";
        else
            descriptor="This is not a new session";
        %>
        <br>
        <h1>Session description:</h1>
        <%=descriptor%>
        <br>
        <hr>
        <%
        String id=session.getId();
        %>
        <br>
        <h2>The session Id is:</h2>
        <%=id%>
        <br>
       
    </body>
</html>

Simple Registration Page with Database Connectivity in HTML and PHP: Part 2

<?php

$getuser=$_POST['username'];
$getemail=$_POST['email'];
$getpwd=$_POST['password'];
$getpassword=$_POST['cnfpwd'];
$getname=$_POST['fullName'];


if(strlen($getemail>=7)&&(strstr($getemail,"@")&&(strstr($getemail,"."))))
{
require("connection.php");
$query=mysql_query("SELECT * FROM registeration WHERE username='$getuser'");
$numrows=mysql_num_rows($query);
if($numrows==0)
{
$query=mysql_query("SELECT * FROM registeration WHERE email='$getemail'");
$numrows=mysql_num_rows($query);
if($numrows==0)
{
$code=rand(11111111,99999999);
mysql_query("INSERT INTO registeration(fullName,age,gender,DOB,address,phone,qualification,workExperience,Institute,email,username,maritalStatus,expertise,password,active,code,date) VALUES ('$_POST[fullName]','$_POST[age]','$_POST[gender]','$_POST[DOB]','$_POST[address]','$_POST[phone]','$_POST[qualification]','$_POST[workExperience]','$_POST[Institute]','$_POST[email]','$_POST[username]','$_POST[maritalStatus]','$_POST[expertise]','$_POST[password]','0','$code',SYSDATE())");
$query=mysql_query("SELECT * FROM registeration WHERE username='$getuser'");
$numrows=mysql_num_rows($query);
if($numrows==1)
{
$site="http://localhost/projectname";
$webmaster="abc@xyz.com";
$headers="From: $webmaster";
$subject="Activate Your Account";
$message="Hello $getuser \n\nThank you for registring with us .click the link to activate your account";
$message.="$site/activate.php?code=$code\n";
$message.="You must activate your account to login";
if(mail($getemail,$subject,$message,$hearders))
{
echo"you have been registered";
$getuser="";
$getemail="";
$getpwd="";
$getpassword="";
}
else
echo"An error occoured .your activation email was not sent";
}
else
echo"an error occured";
}
else
echo"There is already an user with that email";
}
}
else
echo"you must enter a valid email address";


?>

connection.php



<?php
mysql_connect("localhost","username","password");
mysql_select_db("databasename");
?>

Simple Registration Page with Database Connectivity in HTML and PHP: Part 1

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>LBSIM-Conference Management System</title>

<link href="css/Navbar.css" rel="stylesheet" type="text/css" />
</head>
<body leftmargin="0" topmargin="0" marginwidth="0" marginheight="0" background="Image/Background.jpg">
<table width="100%" border="0" cellpadding="0" cellspacing="0">
<script>
function validate(){
    if(document.form.fullName.value == ""){
        alert( "Name cannot be empty" );
        document.form.fullName.focus();
        return false;
    }
    if(document.form.age.value == ""){
        alert( "Age cannot be empty" );
        document.form.age.focus();
        return false;
    }
    if(document.form.email.value == ""){
        alert( "Email cannot be empty" );
        document.form.email.focus();
        return false;
    }
 if(document.form.password.value == ""){
        alert( "Password cannot be empty" );
        document.form.password.focus();
        return false;
    }
    if(document.form.username.value == ""){
        alert( "username cannot be empty" );
        document.form.username.focus();
        return false;
    }
    if(document.form.cnfpwd.value == ""){
        alert( "Confirm Password cannot be empty" );
        document.form.cnfpwd.focus();
        return false;
    }
 if(document.form.cnfpwd.value ==document.form.password.value ){
        alert( "Passwords match" );
        document.form.cnfpwd.focus();
        return true;
    }
 if(document.form.password.value.length<8 ){
        alert( "Password should be have atleast 8 character" );
        document.form.password.focus();
        return false;
    }
 if(document.form.cnfpwd.value !==document.form.pwd.value ){
        alert( "Passwords match" );
        document.form.cnfpwd.focus();
        return false;
    }
    if(document.form.phone.value == ""){
        alert( "Phone Number cannot be empty" );
        document.form.phone.focus();
        return false;
    }
 if(document.form.qualification.value == ""){
        alert( "Qualification cannot be empty" );
        document.form.qualification.focus();
        return false;
    }
 if(document.form.gender.value == 0){
        alert( "Please select a gender" );
        document.form.gender.focus();
        return false;
    }
 if(document.form.address.value == 0){
        alert( "Address field can not be left empty" );
        document.form.address.focus();
        return false;
    }
 if(document.form.Institute.value == 0){
        alert( "Institute field can not be left empty" );
        document.form.Institute.focus();
        return false;
    }
 if(document.form.expertise.value == 0){
        alert( "Area of Expertise field can not be left empty" );
        document.form.expertise.focus();
        return false;
    }
 if(document.form.workExperience.value == 0){
        alert( "Please enter your work experience" );
        document.form.workExperience.focus();
        return false;
    }
 
 alert("Registration Successfull !");
 window.open("Login.html");
    return true;   
    }  
</script>
<tr>
<td>
<img src="Image/bannersketch.png" width="90%" height="90" />
</td>
</tr>
<tr>
<td>
<div id="navbar" style="margin-top:10px;margin-bottom:20px">
<ul>
<li><a href ="CMS.html" title="View home Page">Home</a></li>
<li><a href ="Login.html" title="Go to Login page">Login</a></li>

<li><a href="PDF/Document1.pdf" title="Reseach Paper Submission Guidelines to Authors">Guidelines</a></li>
<li><a href ="Help.html" onmouseover="Show()" onmouseout="Hide()">Help</a></li>
<li><a href ="Contact.html" title="Contact technical support">Contact</a></li>
<li><a href ="FAQ.html" title="View Frequently asked questions">FAQ</a></li>
</ul>
</div>
</td>
</tr>
<div>
<tr>
<td>
<form name="form" method="post" align = "center" onsubmit="return validate();" action="reg.php">

<font color="blue"><b>
Name:<input type="text" name="fullName" maxlength="16"></br>
Age:<input type="text" name="age" maxlength="2"></br>
Date Of Birth:<input type="text" name="DOB" maxlenght="10"></br>
<label>Gender:</label>
<input type="radio" name="gender" value="male" /> Male
<input type="radio" name="gender" value="female" /> Female</br>
<label>Marital Status:</label><input type="radio" name="maritalStatus" value="single" />Single
<input type="radio" name="maritalStatus" value="married" /> Married</br>
<label>Qualification:</label></br>
<textarea name="qualification" rows="5" cols="20" maxlength="50"></textarea> </br>
Address:<input type="textarea" name="address" maxlength="50"></br>
Email:<input type="text" name="email" maxlength="30"></br>
Phone Number:<input type="text" name="phone" maxlength="10"></br>
Institute:<input type="text" name="Institute" maxlength="50"></br>
Area of Expertise:<input type="text" name="expertise" maxlength="30"></br>
Work Experience:<input type ="text" name="workExperience" maxlength="2"></br>
<hr/></font>
<font color="red"><i>
<p> Please Create a user account with us that would be used for next time Login</p>
Username:<input type="text" id="username" name="username" maxlength="20" minlength="10">
<br/>
Password:<input type="password" id="pwd" name="password" maxlength="20" minlength="8"></br>
Confirm Password:<input type="password" name="cnfpwd" id="cnfpwd" maxlength="20" minlength="8">
</b></i></font></br>
<input type="submit" value="register" name="register" align="middle">
</table>
</form>
</td>
</tr>
</div>
<tr>
<td>

</div>
</div>
</td>
</tr>
<tr align="center" height="100">
<td>
<div id="copyright" style="background-color:#999999;width:100%">
<div style="border=1px solid gray; margin-top:10px">
<ul>
<b>Copyright </b>
</ul>
</div>
</div>
</td>
</tr>
</body>
</html>

Few Basic linux Commands

1.                   cat -concatenate files and print on the standard Output

Syntax:

cat [OPTION] [FILE]...

Description

Concatenate FILE(s), or standard input, to standard Output.

-A, --show-all

equivalent to -vET

-b,--number-nonblank

number nonempty Output lines

-e

equivalent to -vE

-E, --show-ends

display $ at end of each line

-n, --number

number all Output lines

-s, --squeeze-blank

suppress repeated empty Output lines

-t

equivalent to -vT

-T, --show-tabs

display TAB characters as ^I

-u

(ignored)

-v, --show-nonprinting

use ^ and M- notation, except for LFD and TAB

--help

display this help and exit

--version

Output version information and exit

With no FILE, or when FILE is -, read standard input.

Output:

sunshine@ubuntu:/home$ cat /home/sunshine/Desktop/hello1 /home/sunshine/Desktop/hello2 hi  kiran how are you? hi  kiran how are you?

 

2.                   man- Display information from the online reference manuals. man locates and prints the named title from the

Syantax:

man [options] [section] [title]

sunshine@ubuntu:/$ man What manual page do you want?

.Output:

2.cal-  Print a 12-month calendar (beginning with January) for the given year, or a one-month calendar of the given month and year. month ranges from 1 to 12. year ranges from 1 to 9999. With no arguments, print a calendar for the current month.

Syantax:

cal [options] [[month] year]

Options

-j

Display Julian dates (days numbered 1 to 365, starting from January 1).

-m

Display Monday as the first day of the week.

-y

Display entire year.

Output:

sunshine@ubuntu:~$ cal     August 2012       Su Mo Tu We Th Fr Sa            1  2  3  4   5  6  7  8  9 10 11  12 13 14 15 16 17 18  19 20 21 22 23 24 25  26 27 28 29 30 31

 

3.            date -print or set the system date and time

Syantax:

date [options] [+format] [date]

Output:

sunshine@ubuntu:~$ date Sun Aug 19 08:11:01 PDT 2012

 

4.            ls - List contents of directories. If no names are given, list the files in the current directory. With one or more names, list files contained in a directory name or that match a file name.names can include filename metacharacters. The options let you display a variety of information in different formats. The most useful options include -F, -R, -l, and -s. Some options don't make sense together (e.g., -u and -c).

Syantax:

ls [options] [names]

Options:

-1, --format=single-column

Print one entry per line of Output.

-a, --all

List all files, including the normally hidden files whose names begin with a period.

-b, --escape

Display nonprinting characters in octal and alphabetic format.

-c, --time-ctime, --time=status

List files by status change time (not creation/modification time).

--color =when

Colorize the names of files depending on the type of file. Accepted values forwhen are never, always, or auto.

-d, --directory

Report only on the directory, not its contents.

-f

Print directory contents in exactly the order in which they are stored, without attempting to sort them.

--full-time

List times in full, rather than using the standard abbreviations.

-g

Long listing like -l, but don't show file owners.

-h

Print sizes in kilobytes and megabytes.

--help

Print a help message and then exit.

-i, --inode

List the inode for each file.

--indicator-style=none

Display filenames without the flags assigned by -p or -f (default).

-k, --kilobytes

If file sizes are being listed, print them in kilobytes. This option overrides the environment variable POSIXLY_CORRECT.

-l, --format=long, --format=verbose

Long format listing (includes permissions, owner, size, modification time, etc.).

-m, --format=commas

Merge the list into a comma-separated series of names.

-n, --numeric-uid-gid

Like -l, but use group ID and user ID numbers instead of owner and group names.

-o

Long listing like -l, but don't show group information.

-p, --filetype, --indicator-style=file-type

Mark directories by appending / to them.

-q, --hide-control-chars

Show nonprinting characters as ? (default for display to a terminal).

-r, --reverse

List files in reverse order (by name or by time).

-s, --size

Print file size in blocks.

--show-control-chars

Show nonprinting characters verbatim (default for printing to a file).

--si

Similar to -h, but uses powers of 1,000 instead of 1,024.

-t, --sort=time

Sort files according to modification time (newest first).

-u, --time=atime, --time=access, --time=use

Sort files according to file-access time.

--version

Print version information on standard Output, then exit.

-x, --format=across, --format=horizontal

List files in rows going across the screen.

-v, --sort=version

Interpret the digits in names such as file.6 and file.6.1 as versions, and order filenames by version.

-w, --width=n

Format Output to fit n columns.

-A, --almost-all

List all files, including the normally hidden files whose names begin with a period. Does not include the . and .. directories.

-B, --ignore-backups

Do not list files ending in ~ unless given as arguments.

-C, --format=vertical

List files in columns (the default format).

-D, --dired

List in a format suitable for Emacs dired mode.

-F, --classify, --indicator-style=classify

Flag filenames by appending / to directories, * to executable files, @ to symbolic links, | to FIFOs, and = to sockets.

-G, --no-group

In long format, do not display group name.

-H, --dereference-command-line

When symbolic links are given on the command line, follow the link and list information from the actual file.

-I, --ignore pattern

Do not list files whose names match the shell pattern pattern, unless they are given on the command line.

-L, --dereference

List the file or directory referenced by a symbolic link rather than the link itself.

-N, --literal

Display special graphic characters that appear in filenames.

-Q, --quote-name

Quote filenames with "; quote nongraphic characters.

-R, --recursive

List directories and their contents recursively.

-Rfile, --reload-state file

Load state from file before starting execution.

-S, --sort=size

Sort by file size, largest to smallest.

-U, sort=none

Do not sort files.

-X, sort=extension

Sort by file extension, then by filename.

Output:

sunshine@ubuntu:/$ ls bin    dev   initrd.img  media  proc  sbin     sys  var boot   etc   lib         mnt    root  selinux  tmp  vmlinuz cdrom  home  lost+found  opt    run   srv      usr

 

5.                   write - write user [tty] message

Initiate or respond to an interactive conversation with user. A write session is terminated with EOF. If the user is logged into more than one terminal, specify a tty number. See also talk; use mesg to keep other users from writing to your terminal.

6.           Echo –

echo [options] [string]
Send (echo) the input string to standard Output. This is the /bin/echo command. echoalso exists as a command built into bash.

Options

-eEnable character sequences with special meaning. (In some versions, this option is not required in order to make the sequences work.)

-E Disable character sequences with special meaning.

-nSuppress printing of newline after text.

--helpPrint help message and then exit.

--versionPrint version information and then exit.

Output:

sunshine@ubuntu:~$ echo hello hello

 

7.           df

Output:

sunshine@ubuntu:~$ df Filesystem     1K-blocks    Used Available Use% Mounted on /dev/sda1       30858908 3180476  26131784  11% / udev              246496       4    246492   1% /dev tmpfs             101508     756    100752   1% /run none                5120       0      5120   0% /run/lock none              253768     272    253496   1% /run/shm /dev/sr0           21066   21066         0 100% /media/CDROM /dev/sr1          718124  718124         0 100% /media/Ubuntu 12.04 LTS i386

 

8.            pwd-  print name of current/working directory

Output:

sunshine@ubuntu:~$ pwd /home/sunshine

 

9.            free - Display statistics about memory usage: total free, used, physical, swap, shared, and buffers used by the kernel.

Syantax: free [options]

Options:

-b Calculate memory in bytes.

-k Default. Calculate memory in kilobytes.

-m Calculate memory in megabytes.

-o Do not display "buffer adjusted" line. The -o switch disables the display "-/+ buffers" line that shows buffer memory subtracted from the amount of memory used and added to the amount of free memory.

-s time Check memory usage every time seconds.

-t Display all totals on one line at the bottom of Output.

-VDisplay version information.

Output:

sunshine@ubuntu:~$ free              total       used       free     shared    buffers     cached Mem:        507536     501372       6164          0       5692      86872 -/+ buffers/cache:     408808      98728 Swap:       521212     226836     294376

 

10.         gzip - Compress specified files (or data read from standard input) with Lempel-Ziv coding (LZ77). Rename compressed file to filename.gz; keep ownership modes and access/modification times. Ignore symbolic links

Syantax:

gzip [options] [files] gunzip [options] [files] zcat[options] [files]

Options:

 -r, --recursive

When given a directory as an argument, recursively compress or decompress files within it.

-S suffix, --suffix suffix

Append .suffix. Default is gz. A null suffix while decompressing causesgunzip to attempt to decompress all specified files, regardless of suffix.

-t, --test

Test compressed file integrity.

-v, --verbose

Print name and percent size reduction for each file.

-V, --version

Display the version number and compilation options.

Output:

sunshine@ubuntu:/$ gzip /home/sunshine/sample1.odt

 

11.         clear - Clear the terminal display. Equivalent to pressing Ctrl-L.

12.         more - Display the named files on a terminal, one screenful at a time. See less for an alternative to more

Syantax:

more [options] [files]

Options:

+num

Begin displaying at line number num.

-num number

Set screen size to number lines.

+/pattern

Begin displaying two lines before pattern.

-c

Repaint screen from top instead of scrolling.

-d

Display the prompt "[Press space to continue, `q' to quit] " instead of ringing the bell. Also display "[Press `h' for instructions] " in response to illegal commands.

-f

Count logical rather than screen lines. Useful when long lines wrap past the width of the screen.

-l

Ignore form-feed (Ctrl-L) characters.

-p

Page through the file by clearing each window instead of scrolling. This is sometimes faster.

-s

Squeeze; display multiple blank lines as one.

-u

Suppress underline characters.

Output:

sunshine@ubuntu:~$ more Usage: more [options] file...

 

Options:

  -d        display help instead of ring bell

  -f        count logical, rather than screen lines

  -l        suppress pause after form feed

  -p        suppress scroll, clean screen and disblay text

  -c        suppress scroll, display text and clean line ends

  -u        suppress underlining

  -s        squeeze multiple blank lines into one

  -NUM      specify the number of lines per screenful

  +NUM      display file beginning from line number NUM

  +/STRING  display file beginning from search string match

  -V        Output version information and exit

13.         who - Show who is logged into the system. With no options, list the names of users currently logged in, their terminal, the time they have been logged in, and the name of the host from which they have logged in. An optional system file (default is /etc/utmp) can be supplied to give additional information.

Syantax:

who [options] [file] who

Options:

-p, --process

Print active processes spawned by init.

-q, --count

"Quick." Display only the usernames and total number of users.

-r, --runlevel

Print the current runlevel.

-s, --short

Print only name, line, and time. This is the default behaviour.

-t, --time

Print the last system clock change.

-u, --users

Print a list of the users who are logged in.

--version

Print version information and then exit.

Output:

sunshine@ubuntu:~$ who sunshine pts/0        2012-08-19 08:10 (:0)

 

14.         whatis who-Search the short manual page descriptions in the whatis database for each keyword and print a one-line description to standard Output for each match. Like apropos, except that it searches only for complete words. Equivalent to man -f.

Syantax:

whatis keywords

Output:

sunshine@ubuntu:~$ whatis who who (1)              - show who is logged on

 

                                                                                         

15.               cd .. – Takes you to the root directory

Output:

sunshine@ubuntu:~$ cd .. sunshine@ubuntu:/home$

 

16.         sleep - Wait a specified amount of time before executing another command. units may be s(seconds), m (minutes), h (hours), or d (days). The default for units is seconds.

Syantax:

sleep amount[units] sleep option

Options:

--help

Print usage information and exit.

--version

Print version information and exit.

17.         whoami- Print current user ID. Equivalent to id -un.

Output:

sunshine@ubuntu:~$ whoami sunshine

 

18.         bc -is a language (and compiler) whose syntax  resembles that of C, but with unlimited-precision arithmetic. bc consists of identifiers, keywords, and symbols, which are briefly described in the following entries. Examples are given at the end.

19.               Interactively perform arbitrary-precision arithmetic or convert numbers from one base to another. Input can be taken from files or read from the standard input. To exit, type quit or EOF.

Syantax:

bc [options] [files]

Options:

-h, --help

Print help message and exit.

-i, --interactive

Interactive mode.

-l, --mathlib

Make functions from the math library available.

-s, --standard

Ignore all extensions, and process exactly as in POSIX.

-w, --warn

When extensions to POSIX bc are used, print a warning.

-q, --quiet

Do not display welcome message.

-v, --version

Print version number.

Output:

sunshine@ubuntu:~$ bc bc 1.06.95 Copyright 1991-1994, 1997, 1998, 2000, 2004, 2006 Free Software Foundation, Inc. This is free software with ABSOLUTELY NO WARRANTY. For details type `warranty'.

 

20.         ls *odt - Lists all the odt  files in the current directory.

Output:

sunshine@ubuntu:/home$ ls * command.odt.gz

 

21.         uname - Print information about the machine and operating system. Without options, print the name of the kernel (Linux).

Syantax:

uname [options]

Options:

-a, --all

Combine all the system information from the other options.

-i, --hardware-platform

Print the system's hardware platform.

-m, --machine

Print the name of the hardware that the system is running on.

-n, --nodename

Print the machine's hostname.

-o, --operating-system

Print the operating system name.

-p, --processor

Print the type of processor.

-r, --kernel-release

Print the release number of the kernel.

-s, --kernel-name

Print the name of the kernel (Linux). This is the default action.

-v, --kernel-version

Print build information about the kernel.

--help

Display a help message and then exit.

--version

Print version information and then exit.

Output:

sunshine@ubuntu:~$ uname -m i686 sunshine@ubuntu:~$ uname -i i386

 

22.         comm -1 file1 file2-Compare lines common to the sorted files file1 and file2. Output is in three columns, from left to right: lines unique to file1, lines unique to file2, and lines common to both files.comm is similar to diff in that both commands compare two files. But comm can also be used like uniq; comm selects duplicate or unique lines between two sorted files, whereasuniq selects duplicate or unique lines within the same sorted file.

Syantax:

comm [options] file1 file2

Options:

-

Read the standard input.

-num

Suppress printing of column num. Multiple columns may be specified and should not be space-separated.

--help

Print help message and exit.

--version

Print version information and exit.

sunshine@ubuntu:~$ comm /home/sunshine/Desktop/hello1 /home/sunshine/Desktop/hello2 hi      Hi  kiran comm: file 1 is not in sorted order how are you?     ravi  comm: file 2 is not in sorted order     I am fine

Output:

23.         ps -Report on active processes. ps has three types of options. GNU long options start with two hyphens, which are required. BSD options may be grouped and do not start with a hyphen, while Unix98 options may be grouped and require an initial hyphen. The meaning of the short options can vary depending on whether or not there is a hyphen. In options, list arguments should either be comma-separated or space-separated and placed inside double quotes. In comparing the amount of Output produced, note that e prints more than a and lprints more than f for each entry.

Syantax:

ps [options]

Output:

sunshine@ubuntu:~$ ps   PID TTY          TIME CMD  1927 pts/0    00:00:00 bash  2266 pts/0    00:00:00 ps

 

24.         diff-Compare two text files. diff reports lines that differ between file1 and file2. Output consists of lines of context from each file, with file1 text flagged by a < symbol and file2 text by a >symbol. Context lines are preceded by the ed command (a, c, or d) that would be used to convert file1 to file2. If one of the files is -, standard input is read. If one of the files is a directory, diff locates the filename in that directory corresponding to the other argument (e.g., diff my_dir junk is the same as diff my_dir/junk junk). If both arguments are directories, diff reports lines that differ between all pairs of files having equivalent names (e.g., olddir/program and newdir/program); in addition, diff lists filenames unique to one directory, as well as subdirectories common to both

Syantax:

diff [options] [diroptions] file1 file2

Output:

sunshine@ubuntu:~$ diff /home/sunshine/Desktop/hello1 /home/sunshine/Desktop/hello2 1,3c1,3 < hi  < kiran < how are you? --- > Hi  > ravi  > I am fine

 

                                                                                    

25.         top –Provide information (frequently refreshed) about the most CPU-intensive processes currently running. You do not need to include a - before options.

Syantax:

top [options]

Options:

-b

Run in batch mode; don't accept command-line input. Useful for sending Output to another command or to a file.

-c

Show command line in display instead of just command name.

-d delay

Specify delay between refreshes.

-f

Add or remove fields or columns.

-h

Print a help message and exit.

Output:

Swap:   521212k total,   188748k used,   332464k free,    83616k cached   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND               886 root      20   0  244m 105m 3304 S  5.8 21.3   2:37.32 Xorg                 2469 sunshine  20   0 54724  17m 8896 S  2.9  3.6   0:01.04 python               1920 sunshine  20   0 89612 7632 4460 S  1.6  1.5   0:05.18 gnome-terminal       2043 sunshine  20   0  424m 108m  14m S  1.6 21.8   1:18.76 firefox              1575 sunshine  20   0  6756 2184  564 S  1.3  0.4   0:06.38 dbus-daemon          1525 sunshine  20   0 54904 1188  944 S  1.0  0.2   0:00.16 gnome-keyring-d      1624 sunshine  20   0  273m  24m 6052 S  1.0  4.9   0:27.95 unity-2d-shell       1647 sunshine  20   0 49824 2288 1088 S  1.0  0.5   0:14.47 bamfdaemon

 

26.               init - System administration command. Initialize system. Usually run from the boot loader—e.g.,lilo or grub.

Boot flags

-a,auto

Set the AUTOBOOT environment variable to yes. The boot loader will do this automatically when booting with the default command line.

-b

Boot directly into a single-user shell for emergency recovery.

-s,S,single

Single-user mode.

-b,emergency

Boot into single-user mode but do not run any other startup scripts.

-z characters

The specified characters are ignored, but will make the command line take up a bit more room on the stack. init uses the extra space to show the current runlevel when running the ps command.

Files

init is the first process run by any Unix machine at boot time. It verifies the integrity of all filesystems and then creates other processes, using fork and exec, as specified by/etc/inittab. Which processes may be run is controlled by runlevel. All process terminations are recorded in /var/run/utmp and /var/log/wtmp. When the runlevel changes, init sends SIGTERM and then, after 20 seconds, SIGKILL to all processes that cannot be run in the new runlevel.

Runlevels

The current runlevel may be changed by telinit, which is often just a link to init. The default runlevels vary from distribution to distribution, but these are standard:

0

Halt the system.

1, s, S

Single-user mode.

3

Multiuser mode, console login. This is commonly used in server configurations.

5

Full graphical mode. This is a common default for desktop configurations.

6

Reboot the system. Never set the default runlevel to 6.

q, Q

Reread /etc/inittab.

Check the /etc/inittab file for runlevels on your system.

Output:

sunshine@ubuntu:~$ init init: Need to be root

 

                                                              

27.         su-Create a shell with the effective user ID user. If no user is specified, create a shell for a privileged user (i.e., become a superuser). Enter EOF to terminate. You can run the shell with particular options by passing them as shell_args (e.g., if the shell runs bash, you can specify -c command to execute command via bash, or -r to create a restricted shell).

Options:

-, -l, --login

Go through the entire login sequence (i.e., change to user's environment).

-c command, --command=command

Execute command in the new shell and then exit immediately. If command is more than one word, it should be enclosed in quotes. For example:

su -c 'find / -name \*.c -print' nobody

-f, --fast

Start the shell with the -f option, which suppresses the reading of the .cshrcor .tcshrc file. Applies to csh and tcsh.

-m, -p, --preserve-environment

Do not reset environment variables.

-s shell, --shell=shell

Execute shell, not the shell specified in /etc/passwd, unless shell is restricted.

--help

Print a help message and then exit.

--version

Print version information and then exit.

Syantax:

su [option] [user] [shell_args]

28.         runlevel-System administration command. Display the previous and current system runlevels as reported in the utmp file. The default utmp file is /var/run/utmp. See init for a summary of runlevels.

Syantax:

runlevel [utmp]

Output:

sunshine@ubuntu:/$ runlevel N 2

 

29.         history – Displays the history of the commands executed on the shell.

Output:

sunshine@ubuntu:~$ history 5    42  time    43  bc    44  history    45  $PATH    46  history 5

 

30.         $PATH

Output:

sunshine@ubuntu:~$ $PATH bash: /usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games: No such file or directory

 

31.         Touch-change file timestamps

For one or more files, update the access time and modification time (and dates) to the current time and date. touch is useful in forcing other commands to handle files a certain way; for example, the operation of make, and sometimes find, relies on a file's access and modification time. If a file doesn't exist, touch creates it with a file size of 0.

Syantax:

touch [options] files

Options:

-a, --time=atime, --time=access, --time=use

Update only the access time.

-c, --no-create

Do not create any file that doesn't already exist.

-d time, --date time

Change the time value to the specified time instead of the current time. timecan use several formats and may contain month names, time zones, a.m. and p.m. strings, etc.

-m, --time=mtime, --time=modify

Update only the modification time.

-r file, --reference file

Change times to be the same as those of the specified file, instead of the current time.

-t time

Use the time specified in time instead of the current time. This argument must be of the format [[cc] yy] mmddhhmm[.ss] , indicating optional century and year, month, date, hours, minutes, and optional seconds.

--help

Print help message and then exit.

--version

Print the version number and then exit.

Output:

sunshine@ubuntu:~$ touch /home/Desktop/sunshine/hello1

 

32.         tail-Output the last part of files

Syantax:

tail [options] [files]

Output:

sunshine@ubuntu:~$ tail /home/sunshine/Desktop/hello1 to you since  it has been long  we have  not spoken to each other

 

                                                                   

33.         head- Output the first few lines of files

Syantax:

head [options] [files]

Output:

sunshine@ubuntu:~$ head /home/sunshine/Desktop/hello1 hi  kiran how are you? I  wanted  to talk to you since  it

 

34.         sort -Sort the lines of the named files. Compare specified fields for each pair of lines; if no fields are specified, compare them by byte, in machine-collating sequence. If no files are specified or if the file is -, the input is taken from standard input. See also uniq, comm, and join.

Syntax:

sort [options] [files]

Options:

-b, --ignore-leading-blanks

Ignore leading spaces and tabs.

-c, --check

Check whether files are already sorted and, if so, produce no output.

-d, --dictionary-order

Sort in dictionary order.

-f, --ignore-case

Fold; ignore uppercase/lowercase differences.

-g, --general-numeric-sort

Sort in general numeric order.

--help

Print a help message and then exit.

Output:

sunshine@ubuntu:~$ sort -c /home/sunshine/Desktop/hello1 sort: /home/sunshine/Desktop/hello1:3: disorder: how are you?

 

35.         yes- Output a string repeatedly until killed

36.         Cp- copy files and directories

Copy file1 to file2, or copy one or more files to the same names under directory. If the destination is an existing file, the file is overwritten; if the destination is an existing directory, the file is copied into the directory (the directory is not overwritten).

Syantax:

cp [options] file1 file2 cp [options] files directory

Options:

-a, --archive

Preserve attributes of original files where possible. The same as -dpr.

-b, --backup

Back up files that would otherwise be overwritten.

-d, --no-dereference

Do not dereference symbolic links; preserve hard-link relationships between source and copy.

-f, --force

Remove existing files in the destination.

-i, --interactive

Prompt before overwriting destination files. On most systems, this flag is turned off by default except for the root user, who is normally prompted before overwriting files.

-l, --link

Make hard links, not copies, of nondirectories.

-p, --preserve

Preserve all information, including owner, group, permissions, and timestamps.

Ouput:

sunshine@ubuntu:~$ cp /home/sunshine/Desktop/hello1 /home/sunshine/Desktop/hello2

 

37.         whoami -print effective userid

Output:

sunshine@ubuntu:~$ whoami sunshine

 

38.         tar- Copy files to or restore files from an archive medium. If any files are directories, tar acts on the entire subtree. Options need not be preceded by - (though they may be). The exception to this rule is when you are using a long-style option (such as --modification-time).

Syantax:

tar [options] [tarfile] [other-files]

39.         time-run programs and summarize system resource usage

Syantax:

time [options] command [arguments]

Output:

sunshine@ubuntu:~$ time real    0m0.001s user    0m0.000s sys    0m0.000s

 

40.         ping - System administration command. Confirm that a remote host is online and responding.ping is intended for use in network testing, measurement, and management. Because of the load it can impose on the network, it is unwise to use ping during normal operations or from automated scripts.

Syantax:

ping [options] host

Options:

-a

Make ping audible. Beep each time response is received.

-A

Adapt to return interval of packets. Like -f ping, sends packets at approximately the rate at which they are received. This option may be used by an unprivileged user.

-b

Ping a broadcast address.

-B

Bind to original source address and do not change.

-c count

Stop after sending (and receiving) count ECHO_RESPONSE packets.

Output:

sunshine@ubuntu:/home$ ping -B Usage: ping [-LRUbdfnqrvVaAD] [-c count] [-i interval] [-w deadline]             [-p pattern] [-s packetsize] [-t ttl] [-I interface]             [-M pmtudisc-hint] [-m mark] [-S sndbuf]             [-T tstamp-options] [-Q tos] [hop1 ...] destination