How To Do Everything | How To Tutorials » Linux/Unix

How to install Wine in Ubuntu

Rohit — Mon, 16 Jan 2012 16:17:12 +0000

Wine is free and open source application for Unix / Linux based Operating Systems which allows us to run applications written for Microsoft Windows. WINE is an acronym for WINdows Emulator. WINE also provides a software library, Winelib, which developers can use to compile Windows applications to port them to Unix / Linux based systems.

In this tutorial, I will show you how to install Wine in Ubuntu using both methods 1. Using Terminal and 2. Manual Installation. Following method is successfully tested on Ubuntu 11.10.

Installing using Terminal:

Start by adding repository for Wine (ppa:ubuntu-wine/ppa) to your Software Sources using following command.
```
sudo add-apt-repository ppa:ubuntu-wine/ppa
```
Add Repository
Now get updates for this repository’s packages using following command.
```
sudo apt-get update
```
Get Updates
Now install the Wine using the following command.
```
sudo apt-get install wine1.3
```
Installing Wine 1.3

It will install Wine1.3, If you want to install other version just replace wine1.3 with wine[version-number].

Installing Manually:

Open Software Sources by searching the same in Dash Home in Ubuntu 11.10 or by navigating to Applications->Ubuntu Software Center and then selecting Edit->Software Sources in lower versions of Ubuntu.
Software Sources
In Software Sources dialogue box, click on the Other Software tab and then click on Add button. Then copy and paste following line in the dialogue box opened and click on Add Source to add Wine repository.
ppa:ubuntu-wine/ppa

Add Repository
Now open following link in your browser. It will open up Ubuntu Software Center. Follow the instructions given to install Wine in your PC.

apt://wine1.3

Replace version number with the one you want to install.

Install Wine1.3

How to install Eclipse in Linux

Rohit — Sun, 15 Jan 2012 16:16:54 +0000

Eclipse is a an IDE i.e Integrated Development Environment tool mostly used by developers for JAVA development. This tool support development in a number of languages like C, C++, COBOL, Java, Perl, PHP, Python, Ruby, etc. and also supports plugins which can let you develop projects in a number of other languages as well.

Eclipse SDK is free and open source software released under the terms of the Eclipse Public License. In this tutorial, I will explain you how to install this IDE in your Linux based system. All the steps are successfully tested on Ubuntu 11.10 and Eclipse 3.7.1.

Instructions:

Download Eclipse package from their website. You must select a version according to your need like if you want to develop C/C++ applications then you must select Eclipse IDE for C/C++ Developers, if you want to develop applications if JAVA, then you must select Eclipse IDE for JAVA Developers or Eclipse IDE for JAVA EE Developers and if you want to develop applications in third-party languages like Android from Google or some other language plugins, then you must select Eclipse Classic.
Now open your Terminal application, move to the directory where you have downloaded eclipse archive using cd command and extract the package downloaded using the tar command. In my case the command is as follows
```
tar xzf eclipse-SDK-3.7.1-linux-gtk.tar.gz
```
Extract Eclipse

Change the name of file eclipse-SDK-3.7.1-linux-gtk.tar.gz with the one you just downloaded.
You can also extract the package by right clicking and then selecting Extract Here.
After extracting, move the extracted directory to /opt/ directory/. After that change the owner of the directory to root using chown command recursively (by using -R option with chown command) and then add read permission to all the directories and files present in the Eclipse directory by using chmod command with -R option.
```
sudo mv eclipse /opt/
sudo chown -R root:root eclipse
sudo chmod -R +r eclipse
```
Move Eclipse to /opt/ Directory

Change Permissions and Directory Owner
Now we need to create eclipse executable in /usr/bin/ directory with following commands and then we need to set its permissions to 755. Use the following command to create eclipse executable
```
sudo gedit /usr/bin/eclipse
```
Now place following command lines in the file opened in gedit
```
#!/bin/sh
#export MOZILLA_FIVE_HOME="/usr/lib/mozilla/"
export ECLIPSE_HOME="/opt/eclipse"
$ECLIPSE_HOME/eclipse $*
```
After this use the following command to change executable file permission to 755
```
sudo chmod 755 /usr/bin/eclipse
```
Creating Eclipse Executable

Now we need to create Gnome menu item for eclipse. Use the following command to create eclipse.desktop file in /usr/share/applications/ directory

sudo gedit /usr/share/applications/eclipse.desktop

Paste in the following lines in that file and then save and quit gedit

[Desktop Entry]
Encoding=UTF-8
Name=Eclipse
Comment=Eclipse IDE
Exec=eclipse
Icon=/opt/eclipse/icon.xpm
Terminal=false
Type=Application
Categories=GNOME;Application;Development;
StartupNotify=true

Create Gnome Menu Item

That’s all Eclipse is successfully installed in your system. You can launch it from command line using the following command
```
/opt/eclipse/eclipse -clean &
```

How to install or update Firefox in Linux using Terminal

Rohit — Sat, 14 Jan 2012 11:53:13 +0000

In this tutorial, I will show you how can you install or update latest version of Firefox in Linux using Terminal commands. Method explained is tested on Ubuntu 11.10 to install Firefox 10.0 and it probably work on all the Linux based Operating Systems.

If you already have older version of Firefox installed in your system, then it should not be running while getting this update. If you are not sure whether latest version is available or not, you can check for the latest version at Firefox website.

Instructions:

To start getting latest version of Firefox in you system, you should add required repository in your system. Following command let you do that.
```
sudo add-apt-repository ppa:mozillateam/firefox-next
```
When your Terminal ask you to press Enter as shown in following image, just press Enterto continue adding required repository. This command will add the PPA repositories inside your /etc/apt/sources.list.d/ directory, in a file named mozillateam-firefox-next-oneiric.list.

Adding Repository
After adding repository, its time to get updates. Using following command will get all the updates required.
```
sudo apt-get update
```
Get Updates
After getting all the updates, its time to finally install latest Firefox in your system. Use the following command to install Firefox in your system.
```
sudo apt-get install firefox
```
This command will show you all the packages which will be installed, which will be upgraded and which ones are no longer required and finally ask you whether you want to continue installation or not. If you are sure that you want to update Firefox or install it, then press 'y' or 'Y' and hit Enter to continue installation.
Installing Firefox
This which will take a little bit of time (depending on your Internet connection) in downloading the installation package and then finally install them.

How to create a Terminal Clock using Shell Script

Rohit — Wed, 11 Jan 2012 17:42:21 +0000

date command displays current date and time to the Terminal and we can use this command to recursively display time every second on Terminal which will look like a Terminal Clock. In this tutorial, I will show you how to create a Shell Script which will make the terminal to show system time every second like a clock.

Default output of date command prints result in the format shown in following image.

date command

But if we use +%r option with date command, the output format changes to format of the system locale as shown in following image.

date command to show time in the format of the system locale

Instructions:

Tell the Terminal to use bash to execute the commands of the script file.
```
#!/bin/bash
```
Now clear the Terminal using clear command so that output of the date command will shown at the top of the Terminal window.
```
clear
```
Now using a while loop which will run infinitely print the time using the following command in which echo command is used with -e option which enable interpretation of backslash escapes (\b) and \c option prevent the echo command to enter a newline character.
```
echo -e "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b`date +%r` \c"
```
We have to sleep the Shell for a second before next iteration of while loop takes place. So, the full while loop looks like
```
while true
do
    echo -e "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b`date +%r` \c"
    sleep 1
done
```

Following image is a screenshot of the working sample script.

Terminal Clock Output

You can download the sample script file here.

How to find Average of Numbers provided through Command Line using Shell Script

Rohit — Tue, 03 Jan 2012 17:28:02 +0000

In this tutorial, I will show you how to use Shell Script to find Average of any number of arguments (numbers) provided through Command Line. The script will find show an error if no argument is provided, otherwise it will find Average of numbers provided and prints its output on the Terminal.

Algorithm:

Check if the numbers of arguments supplied are equal to 0 or not. If yes, print error message and exit the script, otherwise move to step 2.
Find sum of all the numbers provided and store the result in variable total.
Now divide the variable total by number of arguments supplied which is the average of numbers provided.

Instructions:

Tell the Terminal to use bash as shell to execute the script using following line of code.
```
#!/bin/bash
```
Now create three variables total, average and number. total variable to store sum of all the numbers, average to store average of all the numbers and number to store total number of arguments supplied. Initialize total and average to 0 and number to number of arguments supplied.
```
total=0
average=0
number=$#
```

Now check if number of arguments supplied are equal to 0 or not, if yes then print an error message and exit the program.

if [ $# -eq 0 ]
then
    echo "Usage: $0"
    echo "At least one argument required"
    echo "Example $0 number1 number2 ..."
    exit 1
fi

Now using for loop, loop through all the variables provided and find sum of all the numbers supplied using the following code.
```
for temp in $*
do
    total=`expr $total + $temp`
done
```
Now find average by dividing the variable total by variable number and finally print the result.
```
average=`expr $total / $number`
echo "Average of all the numbers is $average"
```

Here are some screenshots of the sample code.

Find Average Using Shell Script

You can download the sample script from here.

How to check for leap year in Shell Script

Rohit — Fri, 23 Dec 2011 12:04:54 +0000

In this tutorial, I will show you a simple shell script to check whether a given number provided through command line denotes a leap year or not using shell script. Algorithm is fairly simple

Check whether the number of command line arguments are equal to 1 or not
If not equal to 1, then print an error message and exit, otherwise proceed to next step.
Store the value of the remainder by dividing number provided through terminal by 4. i.e check=`expr $1 % 4`
Now check whether the value of this check variable is equal to 0 or not. If it is equal to 0 then provided number is a leap year, otherwise not.

Instructions:

Tell the terminal to user bash shell to execute the program using the following line of code.
```
#!/bin/bash
```

Now check whether the number of arguments supplied are equal to 1 or not. If not, then print an error message and exit.

if [ $# -ne 1 ]
then
    echo "Usage : $0"
    echo "Script to check whether a year is leap year or not"
    echo "Enter a single year to check"
    exit 1
fi

Now assign the remainder of number supplied divided by 4 to a variable named check.
```
check=`expr $1 % 4`
```
Now check whether the value of this variable check is equal to 0 or not, if it is then the number supplied is a leap year, otherwise not.
```
if [ $check -ne 0 ]
then
    echo "$1 is not a leap year"
else
    echo "$1 is a leap year"
fi
```

Here is a screenshot of the working of this script.

Check Leap Year using Shell Script

You can download the sample script from here.

The who command – Terminal

Rohit — Tue, 20 Dec 2011 22:24:25 +0000

who is command or tool in Unix/Linux-based operating systems which enables the user to know who is currently logged in their system i.e who is on the System. If no option is supplied to this command, it will display the names of users currently logged in the system, along with their terminal, the time of login and the host from which they have logged in.

*** Note all the following information is tested on Ubuntu 11.10. We endeavor to keep the information up-to-date and correct, However, we cannot guarantee that information given on the site is accurate or up to date.

Syntax : who [options] [file]

Here file specify a path name of a file which can be supplied to give additional information. Default one is /etc/utmp.

General Output format : name [state] line time [idle] [pid] [comment]

name is user’s login name

state shows the user’s capability of writing to the terminal

line is name of the line found in /dev

time is time since user’s login

idle is time elapsed since the user’s last activity and . for this means currently the user is using the system i.e not idle

pid is user’s process id

comment comment line in inittab.

Following table shows all the available Options which you can use with who command/tool.

Option Available	Working
-a, –all	Equivalent to -b -d –login -p -r -t -T -u.
am i	Print the name of invoking user only i.e current terminal.
-b, –boot	Print the date and time of last system boot.
-d, –dead	Print the list of dead processes.
-H	Print column headings above the regular output.
-l, –login	Prints list of only those lines on which the system is waiting for someone to login i.e of system login processes.
-m	Same as who am i.
-p, –process	Print the list of currently active processes spawned by Init.
-q, –count	Print only the user names currently logged in and total number of users currently logged in.
-r, –runlevel	Print the current runlevel of Init process.
-s, –short	Print only name, line, and time. Which is the default behaviour
-t, –time	Print the last system clock change.
-u, –users	Print the list of currently logged in users.

Here are some of the working examples of this command:

who -m command
This command displays information of invoking user only. Following image illustrates this.

who -m command
who -q command
This command displays the user names currently logged in and total number of users currently logged in. In the following image, this command was run in the left terminal when other terminal was not open and in the other terminal when I logged in using other user id, it displays information about two users.

who -q command

Some other images of showing working of this command.

who command

who -b command

who -H command

who -p command

How To reverse the digits of a number using Shell Scripting

Rohit — Tue, 20 Dec 2011 19:12:45 +0000

In this tutorial, I will share a simple script to reverse a number provided through command line in Unix/Linux Operating System. The script will print the reversed digits of provided number and if no number or more than one numbers are provided, then it will print an error. Algorithm is fairly simple :

Let n be the given number.
Set rev and rem equals to 0.
Find last digit of n and store in rem as rem = n % 10.
Now calculate rev as rev = rev * 10 + rem.
Remove the last digit from n by using n = n / 10.
Check if n is greater than 0, if yes goto step 3, else step 7.
Print the number rev which is reverse of number n.

Instructions:

Enter the following line which tell the terminal while running the script to use bash to run the script.
```
#!/bin/bash
```

Now check if only a single argument is provided, if yes then its Ok, otherwise print an error message regarding this and exit the script.

if [ $# -ne 1 ]
then
    echo "Usage : $0 number"
    echo "To print the reverse of input number"
    echo "example for 1234 answer will be 4321"
    echo "provide a single number as parameter to script"
    exit 1
fi

Now assign the 1st parameter value to n, 0 to rev and rem both. (here n, rev, rem are temporary variables)
```
n=$1
rev=0
rem=0
```
Now in a while loop, which will run until value of n is greater than 0, apply the algorithm discussed above as follows.
```
while [ $n -gt 0 ]
do
    rem=`expr $n % 10`
    rev=`expr $rev \* 10 + $rem`
    n=`expr $n / 10`
done
```
Now print the value of variable rev which contains the digits in the reverse order as compared to original number provided.
```
echo "Reversed number is : $rev"
```

Here is an image of the working sample of the script. (Script name is reverse stored in Documents folder)

Reverse Number using Shell Scripting

You can download the sample script from here.

How to enable automatic login in Ubuntu

Rohit — Sun, 18 Dec 2011 18:58:47 +0000

By default Automatic Login feature is disabled for every user you create in Ubuntu for security reasons, but you can enable this feature which will not ask you to enter your account password when you try to login next time in your account. Enabling Automatic Login is not a best practice. But if you are sure that no one has physical access to your PC then you can enable this feature as explained below.

Instructions:

Click on the User name on the top bar in top right corner as shown in following image.
User Account Link
From the pop up menu, click on the User Accounts link to open User Accounts dialogue.
User Accounts Pop up
In the User Accounts dialogue, select the user for which you want to enable automatic login.
User Accounts dialogue
Then click on the Unlock button on the top right part of the dialogue as shown in the following image to enable changes for this user account. It will ask you to authenticate you request by entering your password. Do it and proceed to next step.
Unlock Changes
Now click on the grey area saying “OFF” for Automatic Login which will change the text to “ON” as shown in following image.
Enable Automatic Login
After enabling automatic login for an account, you will see a “tick” sign as shown in following image.
Automatic Login Enabled Sign

The passwd Command – Terminal

Rohit — Fri, 16 Dec 2011 22:19:36 +0000

passwd is command or tool in Unix/Linux-based operating systems which enables the user to change or configure Password of a User account. The password entered by user is run through a Key Derivation Function which converts the plain text to equivalent hash which is encrypted one. Original password is not saved anywhere for security reasons, only this hashed version of new password is stored in /etc/passwd file. Hashed version of plain text is usually calculated by using DES algorithm.

Syntax : passwd [options] [LOGIN]

Here LOGIN is the user-id whose password you want to change. If you want to change password of current user account, then there is no need to mention you user-id, but if you want to change password information of another user’s account, then you have to mention user-id.

Following table shows all the available Options which you can use to configure password of a user account with passwd command/tool.

Option Available	Working
-a, –all	report password status on all accounts can be used with -S option only
-d, –delete	delete the password for the named account
-e, –expire	force expire the password for the named account
-r, –repository REPOSITORY	change password in REPOSITORY repository Available Repositories : files, nis or nisplus.
-l, –lock	lock the password of the named account
-S, –status	report password status on the named account

Here are some of the working examples of this command

Changing the password of current account without using any option
For this you can refer to another article which can be found here.
Changing the password of current account without using any option
Type in the following command to change password for another user’s account. For this you must have Super User rights, otherwise it will show an error “You may not view or modify password information for [user-id]“. In the following example, I am changing password of the User account with user-id howtoideas.

sudo passwd howtoideas

It will ask you the password of the current account to use sudo command and then it will ask you to enter new password of the other user account twice, and then it will show you an output message as shown in following image.

Change Password of another account
Deleting password using -d option
Next time your Operating System will not ask for a password to log into this account. In the following example I am changing the deleting the password of howtoideas user account. If you want to delete password of your own account, then there is no need to add user-id at the end of command.

sudo passwd -d howtoideas

Here is an image of the tested command.

Delete Password
Forcefully expires the password of a user account using -e option
This will expire the current password of the user account and next time when this user tries to log into his account, System will ask the user to enter new password as enforced by root. Following command will expire the password of howtoideasuser account.

sudo passwd -e howtoideas

Following image shows the working of this command.

Change Password Expiration Information

In following image, I am trying to log into howtoideas account, and see Terminal is asking to change the current password as enforced by root.

Change password root enforced
Lock account password using -l option
This option will lock the user account password and user will not be able to log into his account even after providing correct information. In the following command I am locking the howtoideasuser account password.

sudo passwd -l howtoideas

Following image shows the output of upper command.

lock user account password

Now if i try to log into howtoideas account, I won’t be able to do so, even after providing correct password as shown in the following image.

Locked Account Password

Checking status of a particular account or all the accounts using -S option
This option will show the status information of a user account. The information shown is in the following order

name status mm/dd/yy min max warn

name	The login ID of the user.
status	Status of the name: PS or P = Password Enabled account LK or L = Locked NP = No Password NL = No login account
mm/dd/yy	The month date and year that the password was last changed.
min	The minimum number of days between password changes.
max	The maximum number of days the password is valid for the name.
warn	The number of days relative to max before the passwd uses pam for password management.

Following command will showing the information of howtoideas account.

sudo passwd -S howtoideas

Following image shows the output of upper command. See the L character in image after howtoideas in the output which shows that the account is locked. This is because in previous point I locked this account for example purpose.

Locked account Information

Checking status of a particular account or all the accounts using -S and -a Following command will output the password status information of all the account present in the system.

sudo passwd -S -a

Following image shows the output of upper command

Password Status Information of all user accounts