In Linux, all tasks from execution of services to loading and unloading of modules are carried out by programs and all programs need to be executed. You use the commands to access all the basic features of kernel. Shell scripting is a way to automate such tasks, and bash is one of the language, that has capabilities enough to be called as scripting as well as a language that can be used for programming on the POSIX platform, for small tasks.
Using For Loop:
The basic for loop declaration is shown in the following example. Create a file named ‘forloop.sh’ and add the following script using for loop. Here, for loop will iterate for 10 times and print all values of the variable, counter in single line.
Bash Scripting For Loop
#!/bin/bash
for (( counter=10; counter>0; counter-- ))
do
echo -n "$counter "
done
printf "\n"
Run the file with bash command.
$ bash forloop.sh
Example-2: Reading Array Variable
You can use for loop to iterate the values of an array. Create a new bash file named forloop2.sh with the following code.
ColorList=("Blue Green Pink White Red")
for color in $ColorList
do
if [ $color == 'Pink' ]
then
echo "My favorite color is $color"
fi
done
In this example, the loop retrieves the values from an array variable named ColorList and it will print the output only if Pink value is found in the array elements.
Run the file with bash command.
$ bash forloop2.sh
Example-4: Finding odd and even number using three expressions
The most common syntax of for loop is three expression syntax. First expression indicates initialization, second expression indicates termination condition and third expression indicates increment or decrement. Create a new file named loop4.sh to check the script.
for (( n=1; n<=5; n++ ))
do
if (( $n%2==0 ))
then
echo "$n is even"
else
echo "$n is odd"
fi
done
The loop will iterate for 5 times from the value 1 to 5 and it will check and print even and odd numbers. You will get the following output after executing the script.
I hope you liked this post, then you should not forget to share this post at all.
Thank you so much :-)
Disclaimer
This was written for educational purpose and pentest only.
The author will not be responsible for any damage ..!
The author of this tool is not responsible for any misuse of the information.
You will not misuse the information to gain unauthorized access.
This information shall only be used to expand knowledge and not for causing malicious or damaging attacks. Performing any hacks without written permission is illegal ..!
All video’s and tutorials are for informational and educational purposes only. We believe that ethical hacking, information security and cyber security should be familiar subjects to anyone using digital information and computers. We believe that it is impossible to defend yourself from hackers without knowing how hacking is done. The tutorials and videos provided on www.hackingtruth.in is only for those who are interested to learn about Ethical Hacking, Security, Penetration Testing and malware analysis. Hacking tutorials is against misuse of the information and we strongly suggest against it. Please regard the word hacking as ethical hacking or penetration testing every time this word is used.
All tutorials and videos have been made using our own routers, servers, websites and other resources, they do not contain any illegal activity. We do not promote, encourage, support or excite any illegal activity or hacking without written permission in general. We want to raise security awareness and inform our readers on how to prevent themselves from being a victim of hackers. If you plan to use the information for illegal purposes, please leave this website now. We cannot be held responsible for any misuse of the given information.
- Hacking Truth by Kumar Atul Jaiswal