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

Dbms, Explain displaying an er schema as an er diagram, Database Management...

Explain displaying an er schema as an er diagram, Database Management System

Hardware basics, HARDWARE BASICS In the foregoing section of this Unit...

HARDWARE BASICS In the foregoing section of this Unit, an attempt has been made to explain to you the historic perspective relating to the development of computer from its ear

Cryptography, For which X,Y in {o, O, Theta, Omega, omega}, do the relation...

For which X,Y in {o, O, Theta, Omega, omega}, do the relationships t(n)+t''(n) = X(min(t(n),t''(n))) and t(n)+t''(n) = Y(max(t(n),t''(n))) hold for all t,t'' such that t(n),t''(n)

Socket programming, Important: • No cheating will be tolerated. • No late s...

Important: • No cheating will be tolerated. • No late submissions. Total Points for this programming assignment: 100 The goal of your programming assignment is to build and experim

Digital design system, Manipulate the following Boolean expression in such ...

Manipulate the following Boolean expression in such a way so that it can be implemented using exclusive-OR and AND gates only. AB''CD'' + A ''BCD'' + AB''C''D + A''BC''D

Server, Server In a network, the resources of computers comprising net...

Server In a network, the resources of computers comprising network are usually shareable. In fact, one of the main objectives of networking is to make the computing resources

Homework, #questioPurpose of this assignment: 1. Using dictionaries. Assign...

#questioPurpose of this assignment: 1. Using dictionaries. Assignment: Write a program to read a text file and create a dictionary. The keys for the dictionary should be all

Information system and information technology, What is the difference betwe...

What is the difference between information technology and information systems? Describe some of the fuctions of information systems

Working principle of master slave j-k flip flop, Problem 1. Obtain the ...

Problem 1. Obtain the set of prime implicants for f = Σ m (0,1,6,7,8,9,13,14,15) . Obtaining the set of prime implicants: 2. Draw the logic diagram of a divide by

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