Assignment 0 Part 2

Create a small Shell using C language

NAME : HARDIK SAINI

ROLL NO. : 2018391

Pre-requisite in order to perform error free compilation (Make sure that there is enough memory present to fork a child process)

1. ) See the headers included in file. Make sure that you have installed all the required modules/packages before including them else it would give error that module not found below are the all headers that included in file

#include<stdio.h>

#include<string.h>

#include<stdlib.h>

#include<unistd.h>

#include<sys/types.h>

#include<sys/wait.h>

make sure that make is installed sudo apt-get install make

1. ) If the packages are not installed then the program won't compile
2. ) Upon extracting the zipped file open the folder 2018391_CAOS_Shell it would be containing

a. basicFunctions.c

b. basicFunctions.h

c. OuterCommandHandler.c

d. OuterCommandHandler.h

e. shell.c

f. Makefile

1. ) Open terminal here and execute command "make"
2. ) Upon executing command if you have installed all packages correctly it would have created a file "Shell" without extension file
3. ) Execute Shell file by typing ./Shell
4. ) now Shell is running…

Assumption is that you're executing make file in same directory.

COMMANDS DESCRIPTION

COMMAND NAME	FLAGS	DESCRIPTION
echo	\n	New line
\b	Backspace
\c	Suppress Output
history	-c	Clear history
-l	First 5 commands
pwd	Flags not available	Current working directory
exit	Flags not available	Exit from shell
cd	Flags not available	Changes directory
ls	-l	Shows list of all files present
-a	Show all files (hidden too)
cat	--help (No other flag available)	Opens help
--version (No other flag available)	Opens Version of current cat
date	--date={option} (multiple)	Displays date according to option
--help	Opens help
--version	Opens Version of date
rm	-i	Asks before deleting
-r	Deletes recursively
mkdir	--help (Flags not available)	Display help
	--version (Flags not available)	Display version
clear	No flags available	Clear output screen

---

Test cases

1. ) echo apple
2. ) echo apple\nbanana
3. ) echo appe\ble
4. ) history
5. ) history -l
6. ) history -c
7. ) pwd
8. ) cd /bin
9. ) exit
10. ) ls
11. ) ls -l
12. ) ls -a
13. ) ls /
14. ) clear
15. ) cd /
16. ) cat /etc/apt/sources.list
17. ) cat --help
18. ) cat --version
19. ) date --date=yesterday
20. ) date --date=tomorrow
21. ) date --date=1 month ago
22. ) date --date=1 year ago
23. ) date --date=1 year
24. ) date --help
25. ) date --version
26. ) mkdir 1
27. ) mkdir 1/2
28. ) mkdir 1/2/3
29. )rm 1 (Error)
30. )rm -r 1 (Will delete directories recursively)
31. ) rm {file name}
32. ) rm -i {filename}

Protection & defenses

I HAVE CREATED SHELL IN SUCH A WAY THAT IF USER EXECUTES SOMES UNKNOWN COMMAND THE SHELL WON'T CRASH RATHER WILL PRINT THE MESSAGE UNKNOWN COMMAND

PROTECTION AGAINST WRONG COMMAND

Example : ls cat

Error directory not found