Question

1. Write a BASH shell script (see the Important Notes section) that acts as a DOS command interpreter (the user enters the DOS command and the script executes the corresponding Linux command).
   • The script should loop continuously until the user enters the QUIT command
   • Prior to accepting a command, display a prompt containing your first name and the greater than symbol (>)
     • Example prompt: linux>
   • The DOS command, and any arguments, should be stored in variables
     • $command – the DOS command (required)
     • $arg1 – the first argument (optional)
     • $arg2 – the second argument (optional)
       Note: Only some DOS/Linux commands will require one or both argument variables.
   • The script should use case statements to select the appropriate Linux command
     • If an unknown DOS command is entered, display the error message, Command Not Found!
2. Refer to the table below for a list of DOS commands and their Linux counterparts (COMMAND [ARG 1] [ARG 2])
   

1. DOS Command *	Linux Command
   CHDIR [target directory]	cd [target directory]
   CLS	clear
   COPY [source file] [destination file]	cp [source file] [destination file]
   CREATEDIR [directory name]	mkdir [directory name]
   CREATEFILE [file name]	touch [file name]
   DELETE [file name]	rm [file name]
   DIR [file name | directory name | wildcard]	ls [file name | directory name | wildcard]
   MOVE [source] [destination]	mv [source] [destination]
   PRINT [message to print]	echo [message to print]
   QUIT	N/A
   RENAME [old name] [new name]	mv [old name] [new name]
   TYPE [file name]	cat [file name]
   * Assume DOS commands are case-insensitive (i.e., DIR is the same as dir).

Answer 1

#!/bin/bash
quit="quit"

echo -n "Linux> "
read comm
command1=`echo $comm | tr '[:upper:]' '[:lower:]'`

while [ "$command1" != "$quit" ]
do

echo "Linux> "
read comm

arg1=$1
arg2=$2

command1=`echo $comm | tr '[:upper:]' '[:lower:]'`

case $command1 in

chdir)
echo "chdir"
if [ $arg1 -eq "" ]
then
   echo "Please provide direcory name in argument"
else
   cd $arg1
fi
;;

cls)
echo "cls"
clear
;;

copy)
echo "Copy"
if [ $arg1 -eq "" ] && [ $arg2 -eq "" ]
then
   echo "Please provide arg1 and arg2 for source and destination filename"
else
   cp $arg1 $arg2
fi
;;

createdir)
echo "Create dir"
if [ $arg1 -eq "" ]
then
   echo "Please provide direcory name in argument"
else
   mkdir $arg1
fi
;;

createfile)
echo "Create file"
if [ $arg1 -eq "" ]
then
   echo "Please provide file name in argument"
else
   touch $arg1
fi
;;

delete)
echo "Delete"
if [ $arg1 -eq "" ]
then
   echo "Please provide file/directory name in argument to remove."
else
   rm -rf $arg1
fi
;;

dir)
echo "Dir"
;;

move)
echo "Move"
;;

print)
echo "Print"
if [ $arg1 -eq "" ]
then
   echo "Please provide argument to display message."
else
   echo $arg1
fi
;;

type)
echo "Type"
if [ $arg1 -eq "" ]
then
   echo "Please provide file name in argument to display content."
else
   cat $arg1
fi
;;

quit|QUIT)
   exit
;;
*)
echo -n "Command Not Found!"
;;
esac

done

if you have any doubt then please ask me without any hesitation in the comment section below , if you like my answer then please thumbs up for the answer , before giving thumbs down please discuss the question it may possible that we may understand the question different way and we can edit and change the answers if you argue, thanks :)