Unix Shell, Basic Computer Science

Assignment Help:
Write a shell script, change-lines, which will substitute a string for a replacement string for each occurance of the string in files specified.
The original file will be saved, with the same filename with the .keep extension unless the -n option is present.

You may use a temporary file for this script.

Remember the search string and or the replacement string can have special characters in them, so you must use proper quoting techniques.

The script will use following options:


the option -s "string" for the search strings
the option -r "string" for the replacement string
the -n option to prevent a backup file from being created
the -h option to print a usage statement and exit
The script will exit with an error status and print an error message:
if the -s option is not present.
if the -r option is not present.
if the string is not specified with the -s option
if the string is not specified with the -r option
if there are any other options specified
if there are no input files specified
if the input file cannot be read by the current process
if the input file cannot be written by the current process
if you cannot create the backup file.
Here is the usage statement for the script:
change-lines [-n] -s search string -r replace string files ...
-n do not backup the original file
-s search string the search for this string
-r replace string replace the search string with this string
-h print this message

Related Discussions:- Unix Shell

Define server clustering, Question 1 Discuss the impacts of disaster faced...

Question 1 Discuss the impacts of disaster faced by the organization Question 2 Explains the steps involved in disaster recovery planning Question 3 What do you mean by

Binary codes, Binary Codes: We have seen earlier that digital computer...

Binary Codes: We have seen earlier that digital computers use signals that have two distinct values and there exists a direct analogy between binary signals and binary digits.

Why is the atm selected as a transport network in 3g, Why is the ATM select...

Why is the ATM selected as a transport network in 3G? Answer: ATM provides efficient support for transmission of voice, data, and video ATM provides QoS guarantee and reliability

Digital transmission, Digital Transmission: In digital transmission, w...

Digital Transmission: In digital transmission, wave patterns are translated into discrete bits and are separated by intervals. Bits (contraction for binary digits) are the sma

Introduction Assembly Language, This web page looks at assembly languages i...

This web page looks at assembly languages in a common method. Specific illustrations of addressing modes and instructions from a variety of processors are used to demonstrate the g

Modeling historical data, Given the scenario below, construct a conceptual ...

Given the scenario below, construct a conceptual model. The Seville, Spain soccer association is renovating their soccer arena. They are adding luxury boxes that will be offered to

Right click on a folder, I want the detailed theory about the options which...

I want the detailed theory about the options which occur when we right click on a folder.

Command processor and user interface, Command Processor and User Interface:...

Command Processor and User Interface: To the user, the most important and visible services provided by the OS is the user interface and the capabilities that it provides to ex

Mr, Please what is the different between computer science and information t...

Please what is the different between computer science and information technology? Which of this require too much reading? Thanks

Security threats on internet, Security threats on internet:  The Inter...

Security threats on internet:  The Internet has many advantages; however, it also opens up security threat. In this section we just want to highlight some of the threats that

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd