
9. List the types of shells 10. List 11. How do I use the following sings? Give an example on how to use thesm all the ways to communicate with another user who is using the system Page 3 of 4 1466 words %2F0
9. List the types of shells 10. List 11. How do I use the following sings? Give an example on how to use thesm all the ways to communicate with another user who is using the system Page 3 of 4 1466 words %2F0
Types of shells:
==========================================================================
There are various types of shells available in unix. They are listed below:
1. Bourne Shell (sh):
Bourne Shell is the original Unix shell written by Steve Bourne. It was written in the Bell Labs.
2. C Shell (csh):
C Shell provides a C-like language with which to write shell scripts and hence the name is C-SHELL
3. TC Shell (tcsh):
TC shell is available in the public domain. It has all the features of the C shell tand also emacs style editing of the command line.
4. Korn Shell (Ksh):
Korn shell was written by David Korn of Bell labs. It is now provided as the standard shell on Unix systems.
5. Bourne Again SHell (BASH):
Bash is written by Brian Fox for the GNU Project as a free software replacement for the Bourne shell.
==========================================================================
Ways to communicate with another user who is using the same system
===========================================================================
In the system, by default, accepting messages are turned off. This is for the security reasons. You must allow other users to send you message. Use the following command: mesg y
(1). Using WRITE command:
write username [terminal]
example: write pts/1 “Hello Brother.!!”
The above command will make the user using pts/1 to see a message “Hello Brother.!!”
(2). Using echo Command:
From terminal pts/1:
$ sudo echo “Good Mrng Brother” > /dev/pts/4
The above command will make the user using pts/4 to see the message “Good Mrng Brother.!!”
(3) Using wall command:
we can use this command to send a message to all the users.
$ sudo wall -n Hello
Everyone using the system will see hello message but they don’t know who sent the message because we use -n flag here. If you remove -n flag, everyone will know that it’s you.
=========================================================================
Using a semicolon ( ; ):
It is used as the command seperator. It seperates various commands in a single line.
example: $ echo “hello” ; echo “hai”
Here, the shell waits for each command to terminate.The return status is the exit status of the last command executed.
Using parenthesis () :
$(…) means execute the command in the parenthesis in a subshell and return its standard output.
Example: $ echo “Current Date is $(date)”
Using Ampersand (&):
It indicates the command runs in background.
Example: $ sh xyz.sh &
It executes the xyz.sh script in the background. With & the process starts in the background, so you can continue to use the shell and do not have to wait until the script is finished.
Using single quotes ( ‘ ‘ ):
It is used to indicate a string. They are called Strong Quotes.
example: $ echo ‘a b’
The output will be ‘a b’ it is a string.
Using backslah ( ):
It is called single character quote.
If you want to place text on two or more lines for readability, but the program expects one line, you need a line continuation character, we can use the backslash as the last character on the line:
example: $ echo This is
. a very
. Long line.
Using Double Quotes (” “):
These are called weak quotes.
we can use $ echo “hai”
We use these to have QUOTES WITHIN QUOTES.
$ echo ” I can’t go without you dear”
===================================================================
NOTE: Please hit the LIKE button if you like the Solution and appreciate our time. It would really boost us to help you better. If there are any doubts, HIT the LIKE and comment down here.. we are right here to help you.!!!!
Happy Learning..!!
Why Us?
Top Quality and Well-Researched Papers
All ourbpapers are written from scratch. In fact, Clients who ask for paraphrasing services are highly discouraged. We have writers ready to craft any paper from scratch and deliver quality ahead of time.
Professional and Experienced Academic Writers
Our writers keeps you posted on your papers progress - providing you with paper outline/draft. You are also at liberty to communicate directly with your writer.
Free Unlimited Revisions
If you think we missed something, send your order for a free revision. You have 10 days to submit the order for review after you have received the final document. You can do this yourself after logging into your personal account or by contacting our support.
Prompt Delivery and 100% Money-Back-Guarantee
All papers are always delivered on time, in many cases quite ahead of time. In case we need more time to master your paper, we may contact you regarding the deadline extension. In case you cannot provide us with more time, a 100% refund is guaranteed.
Original & Confidential
We use several writing tools checks to ensure that all documents you receive are free from plagiarism. Our editors carefully review all quotations in the text. We also promise maximum confidentiality in all of our services.
24/7 Customer Support
Our support agents are available 24 hours a day 7 days a week and committed to providing you with the best customer experience. Get in touch whenever you need any assistance.
Try it now!
How it works?
Follow these simple steps to get your paper done
Place your order
Fill in the order form and provide all details of your assignment.
Proceed with the payment
Choose the payment system that suits you most.
Receive the final file
Once your paper is ready, we will email it to you.
Our Services
No need to work on your paper at night. Sleep tight, we will cover your back. We offer all kinds of writing services.
Essays
No matter what kind of academic paper you need and how urgent you need it, you are welcome to choose your academic level and the type of your paper at an affordable price. We take care of all your paper needs and give a 24/7 customer care support system.
Admissions
Admission Essays & Business Writing Help
An admission essay is an essay or other written statement by a candidate, often a potential student enrolling in a college, university, or graduate school. You can be rest assurred that through our service we will write the best admission essay for you.
Reviews
Editing Support
Our academic writers and editors make the necessary changes to your paper so that it is polished. We also format your document by correctly quoting the sources and creating reference lists in the formats APA, Harvard, MLA, Chicago / Turabian.
Reviews
Revision Support
If you think your paper could be improved, you can request a review. In this case, your paper will be checked by the writer or assigned to an editor. You can use this option as many times as you see fit. This is free because we want you to be completely satisfied with the service offered.