INDEX
Sl Assignment no. Page Remarks
no.
01 Module 1 01-03
02 Module 2 04-08
03 Module 3 09-17
04 Module 4 18-22
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BASIC LINUX COMMANDS
Sl
No. Command Uses Output
Print current working
1. pwd
directory
2. mkdir <filename> Create a directory
Change current
3. cd <dir path> working directory to
specified path
List files & folders of a
4. ls
directory
print or set the system
5. date
date and time
prints the current
6. date +%m month in two-digit
format
print the current
7. date +%M
minute
print the hour in 24-
8. date +%H
hour format.
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Sl
No. Command Uses Output
Current month’s
9. cal
calendar.
Displays the entire
10. cal 2025 calendar for the year
2025.
Creates a new file &
11. cat > <filename> lets us type input
directly into it.
Displays the contents
12. cat <filename> of the specified file in
the terminal.
Copies file1 into
13. cp file1 D2/file2 directory D2/ with a
new name file2.
Moves & renames
14. mv file1 D5/file2 file1 to file2 inside
directory D5/.
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Sl
No. Command Uses Output
Lists files and directories
in the current directory in
long format.
Output includes file
15. ls -l permissions, Number of
hard links, owner, group,
file size in bytes, Name of
file or dir.
Shows a numbered list
of previously run
16. history
commands in current
shell session.
Gives the user (owner)
execute permission on
the file.
chmod u+x
17. • u -> user
<filename>
• +x -> add
executable
permission
Adds execute (+x)
chmod ugo+x permission for user
18.
<filename> (u), group (g), and
others (o) on the file.
Give full read, write,
and execute
permissions to user,
group, and others.
Each number is a sum
of permissions:
chmod 777
18.
<filename> • 4 → read (r)
• 2 → write (w)
• 1 → execute
(x)
So, 7 = 4 + 2 + 1
gives read, write, and
execute permissions.
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VI COMMAND EDITOR
SL COMMAND USE OUTPUT
NO. NAME
1. vi filename To create
and open a
new file
(ex- vi
hello.txt)
2. i Insert mode
(it give the
access to
type text in
vi terminal)
3. esc Exit insert There is no specific output or massage for the command
mode
To command
mode.it just shows blank and users can opearate many
mode commands.
4. :w To save the
file in vi
terminal
5. : ( colon) Enter
command
line mode
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6. :q To quit the
editor to
linux Output-
terminal
7. : wq Save and quit
the editor.
Output:-
8. : q! Quit the
editor
without
saving .
Now these are command in below after press ”esc” to enter the command mode.
9. x Delete a
single
character of
a line .
After press esc x
10. dd Delete the
entire
current line
After press dd
11. yy To copy the
entire line
There is no immidiate ouput after yy
It will paste the copied line after p
12. p Paste the
copied line in
vi editor
after press yy and then p
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13. u Undo the last
action
After press u
`14. G Go to the
end of the
file After press G
15. gg To go to the
top of the vi
file
After press gg
16. h Move cursor
left
After press h continously
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17. l Move the
cursor right
After press l
18. j Move the
cursor down
After press j
19. k Move the
cursor up
after press k:-
20. r Replaces the
character
under the
cursor with
<char>.
After press r t :-
21. R replace
mode,
where
every
character
you type
overwrites
existing
text.
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22. s Deletes the
character
under the
cursor and
enters insert
mode.
after press s:-
23. S Deletes the
entire line
and enters
insert mode.
AFTER PRESS S THE LINE WILL BE EARSED
22. gcc Gnu compiler
filename.c collection
It helps to
compile a c
program file
in vi editor
23. ./a.out Run the
compiled c
program
Here a is the
ststic library
of c
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CPU SCHEDULING ALGORITHMS
Q. Write a c program for FCFS scheduling algorithm, CPU burst, arrival time (if needed) must be
given by user.
CODE: -
#include <stdio.h>
int main() {
int n, i;
int AT[10], BT[10], CT[10], TAT[10], WT[10];
printf("\nEnter number of processes: ");
scanf("%d", &n);
for (i = 0; i < n; i++) {
printf("Process %d Arrival Time: ", i + 1);
scanf("%d", &AT[i]);
printf(" Burst Time: ");
scanf("%d", &BT[i]);
printf("\n");
CT[0] = AT[0] + BT[0];
TAT[0] = CT[0] - AT[0];
WT[0] = TAT[0] - BT[0];
for (i = 1; i < n; i++) {
if (CT[i-1] < AT[i])
CT[i] = AT[i] + BT[i];
else
CT[i] = CT[i-1] + BT[i];
TAT[i] = CT[i] - AT[i];
WT[i] = TAT[i] - BT[i];
printf("Waiting Times:\n");
for (i = 0; i < n; i++) {
printf(" Process %d: %d\n", i + 1, WT[i]);
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}
return 0;
OUTPUT: -
Q. Write a c program for SJF scheduling algorithm, CPU burst, arrival time (if needed) must be
given by user.
CODE: -
#include <stdio.h>
int main() {
int n, i, time = 0, completed = 0;
int AT[10], BT[10], CT[10], TAT[10], WT[10];
int done[10] = {0};
printf("\nEnter number of processes: ");
scanf("%d", &n);
printf("\n");
for (i = 0; i < n; i++) {
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printf("Process %d Arrival Time: ", i + 1);
scanf("%d", &AT[i]);
printf(" Burst Time: ");
scanf("%d", &BT[i]);
while (completed < n) {
int idx = -1;
int minBT = 9999;
for (i = 0; i < n; i++) {
if (done[i] == 0 && AT[i] <= time && BT[i] < minBT) {
minBT = BT[i];
idx = i;
}}
if (idx != -1) {
time += BT[idx];
CT[idx] = time;
TAT[idx] = CT[idx] - AT[idx];
WT[idx] = TAT[idx] - BT[idx];
done[idx] = 1;
completed++;
} else {
time++;
}}
printf("Waiting Times:\n");
for (i = 0; i < n; i++) {
printf(" Process %d: %d\n", i + 1, WT[i]);
return 0;
OUTPUT: -
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Q. Write a c program for Priority scheduling algorithm, CPU burst, arrival time (if needed) must
be given by user.
Non-Preemptive
CODE: -
#include <stdio.h>
int main() {
int n, i, j, time = 0;
int AT[10], BT[10], CT[10], TAT[10], WT[10], priority[10];
int done[10] = {0};
printf("\nEnter number of processes: ");
scanf("%d", &n);
printf("\n");
for (i = 0; i < n; i++) {
printf("Process %d Arrival Time: ", i + 1);
scanf("%d", &AT[i]);
printf(" Burst Time: ");
scanf("%d", &BT[i]);
printf(" Priority: ");
scanf("%d", &priority[i]);
printf("\n");
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}
for (i = 0; i < n; i++) {
for (j = i + 1; j < n; j++) {
if (priority[i] > priority[j] || (priority[i] == priority[j] && AT[i] > AT[j])) {
int temp = AT[i];
AT[i] = AT[j];
AT[j] = temp;
temp = BT[i];
BT[i] = BT[j];
BT[j] = temp;
temp = priority[i];
priority[i] = priority[j];
priority[j] = temp;
}}}
for(i = 0; i < n; i++) {
if (i == 0 || AT[i] > time) {
time = AT[i];
CT[i] = time + BT[i];
TAT[i] = CT[i] - AT[i];
WT[i] = TAT[i] - BT[i];
time = CT[i];
printf("Waiting Times:\n");
for (i = 0; i < n; i++) {
printf(" Process %d: %d\n", i + 1, WT[i]);
return 0;
OUTPUT: -
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Preemptive
CODE: -
#include <stdio.h>
int main() {
int n, i, time = 0, completed = 0;
int AT[10], BT[10], CT[10], TAT[10], WT[10], priority[10];
int remainingBT[10], done[10] = {0};
printf("\nEnter number of processes: ");
scanf("%d", &n);
printf("\n");
for (i = 0; i < n; i++) {
printf("Process %d Arrival Time: ", i + 1);
scanf("%d", &AT[i]);
printf(" Burst Time: ");
scanf("%d", &BT[i]);
printf(" Priority: ");
scanf("%d", &priority[i]);
remainingBT[i] = BT[i];
printf("\n");
while (completed < n) {
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int idx = -1;
int minPriority = 9999;
for (i = 0; i < n; i++) {
if (done[i] == 0 && AT[i] <= time && priority[i] < minPriority) {
minPriority = priority[i];
idx = i;
if (idx != -1) {
remainingBT[idx]--;
if (remainingBT[idx] == 0) {
CT[idx] = time + 1;
TAT[idx] = CT[idx] - AT[idx];
WT[idx] = TAT[idx] - BT[idx];
done[idx] = 1;
completed++;
time++;
} else {
time++;
}}
printf("Waiting Times:\n");
for (i = 0; i < n; i++) {
printf(" Process %d: %d\n", i + 1, WT[i]);
return 0;
OUTPUT: -
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Q. Write a c program for Round Robin scheduling algorithm, CPU burst, arrival time (if needed)
must be given by user.
CODE: -
#include <stdio.h>
int main() {
int n, i, j, tq;
int AT[10], BT[10], RT[10], WT[10] = {0};
int time = 0, done = 0;
printf("\nEnter number of processes: ");
scanf("%d", &n);
printf("Enter Time Quantum: ");
scanf("%d", &tq);
printf("\n");
for (i = 0; i < n; i++) {
printf("Process %d Arrival Time: ", i + 1);
scanf("%d", &AT[i]);
printf(" Burst Time: ");
scanf("%d", &BT[i]);
RT[i] = BT[i];
printf("\n");
}
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while (done < n) {
int progress = 0;
for (i = 0; i < n; i++) {
if (RT[i] > 0 && AT[i] <= time) {
progress = 1;
int exec = (RT[i] > tq) ? tq : RT[i];
time += exec;
RT[i] -= exec;
for (j = 0; j < n; j++) {
if (j != i && RT[j] > 0 && AT[j] <= time)
WT[j] += exec;
if (RT[i] == 0)
done++;
}}
if (!progress)
time++;
printf("Waiting Times:\n");
for (i = 0; i < n; i++) {
printf(" Process %d: %d\n", i + 1, WT[i]);
printf("\n");
return 0;
OUTPUT: -
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PAGE REPLACEMENT ALGORITHMS
Q. Write a C program for FIFO page replacement algorithm and the needed inputs will be given by users
and calculate the total Page Fault.
CODE: -
#include <stdio.h>
int main() {
int i, j, k, n, frameCount, pageFaults = 0;
int pages[100], frames[10], front = 0;
printf("\nENTER THE NUMBER OF PAGES: ");
scanf("%d", &n);
printf("ENTER THE PAGE NUMBER : ");
for (i = 0; i < n; i++) {
scanf("%d", &pages[i]);
printf("ENTER THE NUMBER OF FRAMES :");
scanf("%d", &frameCount);
for (i = 0; i < frameCount; i++) {
frames[i] = -1;
printf("\nref string page frames\n");
for (i = 0; i < n; i++) {
int found = 0;
for (j = 0; j < frameCount; j++) {
if (frames[j] == pages[i]) {
found = 1;
break;
}}
if (!found) {
frames[front] = pages[i];
front = (front + 1) % frameCount;
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pageFaults++;
printf("%-17d", pages[i]);
for (k = 0; k < frameCount; k++) {
if (frames[k] == -1) {
printf(" -1");
} else {
printf("%4d", frames[k]);
printf("\n");
} else {
printf("%d\n", pages[i]);
}}
printf("\nPage Fault Is %d\n", pageFaults);
return 0;
OUTPUT: -
Q. Write a C program for LRU page replacement algorithm and the needed inputs will be given by users
and calculate the total Page Fault.
CODE: -
#include <stdio.h>
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int main() {
int pages[100], frames[10], time[10];
int i, j, k, n, frameCount, pageFaults = 0, counter = 0;
printf("\nENTER THE NUMBER OF PAGES: ");
scanf("%d", &n);
printf("ENTER THE PAGE REFERENCE STRING: ");
for (i = 0; i < n; i++) {
scanf("%d", &pages[i]);
printf("ENTER THE NUMBER OF FRAMES: ");
scanf("%d", &frameCount);
for (i = 0; i < frameCount; i++) {
frames[i] = -1;
time[i] = 0;
printf("\nRef | Frame State\t\t(Page Fault?)\n");
printf("-----|-------------------------------\n");
for (i = 0; i < n; i++) {
int flag1 = 0, flag2 = 0;
for (j = 0; j < frameCount; j++) {
if (frames[j] == pages[i]) {
counter++;
time[j] = counter;
flag1 = flag2 = 1;
break;
}}
if (flag1 == 0) {
for (j = 0; j < frameCount; j++) {
if (frames[j] == -1) {
counter++;
frames[j] = pages[i];
time[j] = counter;
pageFaults++;
flag2 = 1;
break;
}}}
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if (flag2 == 0) {
int min = time[0], pos = 0;
for (j = 1; j < frameCount; j++) {
if (time[j] < min) {
min = time[j];
pos = j;
}}
counter++;
frames[pos] = pages[i];
time[pos] = counter;
pageFaults++;
printf(" %-4d|", pages[i]);
for (k = 0; k < frameCount; k++) {
if (frames[k] == -1)
printf(" - ");
else
printf(" %2d ", frames[k]);
if (flag1 == 1)
printf("\t\t(Hit)\n");
else
printf("\t\t(Fault)\n");
printf("\nTOTAL PAGE FAULTS = %d\n", pageFaults);
return 0;
OUTPUT: -
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