Question

Task: 2.1 : Shell Scripting

Task1 :Traditional hello world script

1. Open terminal create Lab01 directory and use cd command to move into the directory
2. Open a new file script hello.sh using vi editor

# vi hello.sh

3. Type the following lines

#!/bin/bash           echo Hello World    

4. Save the file and return back to terminal

How to Runhello.sh

Adding Execute Permission

1. Checking current permission       

# ls -la hello.sh

2. Adding Execute permission

# chmod u+x hello.sh  

3. Check whether execute permission is added

# ls -la hello.sh

4. Running or executing the script  

# ./hello.sh

Description : This script has only two lines. The first indicates the system which program to use to run the file. The second line is the only action performed by this script, which prints 'Hello World' on the terminal.

Task2.2 :In this lab exercise, you will create a bash shell script and execute it. The studentswillalso use bash variables to customize their shell prompts.

1. Open a new file script calc.sh using vi editor

# vi calc.sh

2. Type the following lines

#!/bin/bash #a simple script

echo "$1 + $2 = $(($1 + $2)) "

3. Save the file

4. Change the permissions of calc.sh to executable with

#chmod u+x calc.sh

5. From the terminal, run the script with  

# ./calc.sh 2 2

Task 2.3: Write a script that will create a file that is named when you execute the shell script and direct the o/p of ls to that file

1. Open a new file script myshell.sh using vi editor

# vi myshell.sh

2. Type the following lines

#!/bin/bash touch $1 ls > $1

3. Add the execute permission
4. Run the script

# ./myshell.sh testfile

5. Check whether testfile is created
6. Check the contents of the file
7. Run the script again and create a testfile1

Task 2.4 : Write a script that will create a file using today’s date and the date format is ddmmmyy.dat

1. Open a new file script date.sh using vi editor # vi date.sh
2. Type the following lines

#!/bin/bash touch   `date +%d%b%y`.dat FILENAME=`date +%d%b%y`.dat touch $FILENAME

3. Add the execute permission
4. Run the script

#./date.sh

5. Check whether file is created

Task 2.5: Write a script that will ask the user for to input a file name and then create the file and echo to the screen that the file name inputted had been created

1. Open a new file script creafile.sh using vi editor

# vi creafile.sh

2. Type the following lines

#!/bin/bash echo ‘enter a file name: ‘ read FILENAME touch $FILENAME echo “$FILENAME has been created”

3. Add the execute permission
4. Run the script

#./creafile.sh

5. Enter the file name you want to create
6. Check whether file is created

Task 2.6 : In this exercise, you will create a script to echo users, based on a list of usernames in a file.

1. create a new file called userlist.

#viuserlist

2. Insert a short list of usernames, such as the following. Make sure that none are the names of existing users.

moe larry curly

binny

3. create a script file userscript.sh and type the following lines

#!/bin/bash

for TheUSER in $(cat userlist) do

    echo The user is $TheUSER

done

4. Add the permissions and run the script

Answer 1

Task: 2.1 : Shell Scripting

For insert the text in vi editor use i button to insert.

For saving the file in vi editor use :wq to save and quit from vi editor

File content of hello.sh is:

#!/bin/bash #a simple script

echo "$1 + $2 = $(($1 + $2)) "

Task2.2:

File content of calc.sh is:

#!/bin/bash #a simple script

echo "$1 + $2 = $(($1 + $2)) "

Task 2.3:

myshell.sh:

#!/bin/bash #a simple script

touch $1 ls > $1

Check the directory Lab01

testfile is crated

Task 2.4 :

date.sh file content is:

#!/bin/bash

touch `date +%d%b%y`.dat

FILENAME= `date +%d%b%y`.dat

$FILENAME

Task 2.5:

creafile.sh file content is:

#!/bin/bash

echo 'enter a file name: '

read FILENAME

touch $FILENAME

echo "$FILENAME has been created"

Task 2.6:

userlist file content is:

moe

larry

curly

binny

userlist.sh file content is:

#!/bin/bash

for TheUSER in $(cat userlist)

do

    echo The user is $TheUSER

done