This question requires you to write a shell script for bash or zsh$.$

Task: Write a bash $($or zsh$)$ shell script that accepts exactly two arguments from the

command$-$line. The first argument is meant to be a filename of a text file and the second

one is the name of a directory. This script should perform the following:

a$)$ Display an appropriate error message and terminate if the number of arguments is

not exactly $2.$

b$)$ If the file $($specified in argument $1)$ does not exist, then display an appropriate error

message and terminate.

c$)$ Otherwise, save all the lines in that file that contains the word $$special$$ in a file

called special.txt in the directory specified as argument $2.$ If this directory does

not exist in the current directory, then create it$.$

d$)$ If the file special.txt already exists in the directory specified, then those lines of

text extracted from argument $1$ should be appended to special.txt$.$

Submission Requirement: Submit only your script file. Your script file MUST be named

extract.sh

Your script file should be documented with appropriate comments. Make sure your

name and student ID are at the top of the file.

$2024$ AUT $2$

Question $2$: C Struct and Pointers $($Max Mark: $40/100)$

The C programs you are required to write for this question will be compiled using gcc on

either Linux or MacOS for marking.

Task: You are required to write three C functions that maintains a linked list of simple

process information $($i$.$e$.$ a small process control block$).$ You may refer to the code in

prog$4.$c in Lab $3$ as a starting point.

Each process control block $($PCB$)$ should be represented as a C structure that consists

of

$($a$)$ A process ID $($an int$)$

$($b$)$ Process name $($a char array$)$

You will need to provide the definition of this structure and use typedef to give this

structure a name. You will also need to modify the List$\_$item definition in prog$4.$c so that

it contains a pointer to this structure. $($The int is no longer needed.$)$

The three C functions are described as follows:

$($a$)$ The first function, to be named insert, inserts a new PCB into the list. The

position where this PCB is to be inserted depends on its process ID$.$ The resulting

list should be ordered by the process ID$.$ For example, if the process IDs of the

existing items in the list are $1-15-20$ and the process ID of the new PCB is $7.$ Then

it should be inserted after process ID $1$ and before $15,$ resulting in $1-7-15-20.$ The

function prototype of insert should be:

int insert$($struct List$\_$item $*$listHead$,$ struct List$\_$item $*$insertItem$)$;

where listHead points to the head of the linked list, insertItem points to the list

item to be inserted. This function should return $1$ if the insertion is successful

and $0$ if not. Insertion could be unsuccessul due to several reasons, e$.$g$.$

duplicated process ID$.$

$($b$)$ The second function, to be named delete, removes a PCB from the list. The PCB

to be removed is specified by its process ID$.$ The function prototype of delete

should be:

int delete$($struct List$\_$item $*$listHead$,$ int pid$)$;

where pid is the process ID of the PCB to be removed. This function should

return $1$ if the deletion is successful, and $0$ if nothing has been deleted, e$.$g$.$

process ID not found.

$2024$ AUT $3$

$($c$)$ The third function, to be named printList, performs the same function as the last

section of the main$()$ function in prog$4.$c that prints information of the items $($in

this case the process ID and the name of the process$)$ on the list. The function

prototype should be:

void printList$($struct List$\_$item $*$listHead$)$;

The code of these $3$ functions should be in a file named listfuncs.c$.$ The main$()$ function

should be placed in a file named main.c

Further Requirement: You should modify the main$()$ function to provide at least $3$

insertions and $3$ deletions where at least $1$ insertion and $1$ deletion is unsuccessful.

Print the list information after each insertion or deletion using printList to show the

result of that operation.

Your program should use appropriate header file$($s$).$

Submission Requirements: Submit only your main.c$,$ listfuncs.c and associated

header files. Your submission will be compiled using the command:

gcc main.c listfuncs.c $-$o main

So make sure your programs could be compiled without error either on Ubuntu or

MacOS using this command and the resulting program runs as required.

Your source code files should be documented with appropriate comments. Make sure

your name and student ID are at the top of each file.