DOS command to Bash command conversion

Question

I need to make Bash take DOS commands in with arguments and then convert the main command to a Bash command and still use the arguments if there are any arguments.

The part I am lost on is how to pass arguments to the individual cases and not getting stuck by the *) Command Not Found!

For example a user inputs:

copy file1.txt file2.txt

Use case: copy then should run the Linux cp command and use the two arguments passed copy to finish the command.

#!/bin/bash

while :
do
read INPUT_STRING
case $INPUT_STRING in
        chdir|CHDIR)
        cd $arg1
        bash myscript.sh
;;
        cls|CLS)
        clear
        bash myscript.sh
;;
        copy|COPY)
        cp $arg1 $arg2
        bash myscript.sh
;;
        createdir|CREATEDIR)
        mkdir $arg1
        bash myscript.sh
;;
        delete|DELETE)
        rm $arg1
        bash myscript.sh
;;
        dir|DIR)
        ls
        bash myscript.sh
;;
        move|MOVE)
        mv $arg1 $arg2
        bash myscript.sh
;;
        print|PRINT)
        echo $arg1
        bash myscript.sh
;;
        quit|QUIT)
        break
        PS1="n01396736@cisvm-cop4640-2:~$ "
;;
        rename|RENAME)
        mv $arg1 $arg2
        bash myscript.sh
;;
        type|TYPE)
        cat $arg1
        bash myscript.sh
;;
        *)
        echo "Command Not Found!!"
        bash myscript.sh
;;
esac
break
done

Answer 1

Thank you roamia and Michael Prokopec for pointing me in the right direction. This is what I ended up with and it works like it is suppose to. If you see any errors or things I can do to improve the code please let me know. This is my first Linux script I have created.

#!/bin/bash

counter=1
while : [$counter -lt 2]
do
read -p 'Your Name Here > ' cmd "arg"

case $cmd in
chdir|CHDIR)
        cd $arg
        ;;
cls|CLS)
        clear
        ;;
copy|COPY)
        cp $arg
        ;;
createdir|CREATEDIR)
        mkdir $arg
        ;;
createfile|CREATEFILE)
        touch $arg
        ;;
delete|DELETE)
        rm $arg
        ;;
dir|DIR)
        ls
        ;;
move|MOVE)
        mv $arg
        ;;
print|PRINT)
        echo $arg
        ;;
quit|QUIT)
        counter=2
        ;;
rename|RENAME)
        mv $arg
        ;;
type|TYPE)
        cat $arg
        ;;
*)
        echo "Command Not Found!!"
        ;;
esac
done

Answer 2

Your script seems to simply replace command names with alternative names. This is easily done by providing aliases in the shell.

For example:

alias remove=rm
alias type=cat
alias dir='ls -l'
alias cls=clear
alias quit=exit

You could put these into a file called something like dos_compat and then start an interactive bash shell using

bash --rcfile dos_compat

This would start a new interactive shell with the aliases available. Use exit or quit or Ctrl+D to get back to your original shell.

If any DOS command that you'd like to implement is more complex than a simple alias, you would need to implement that as a shell function in the dos_compat file. One use for this would possibly be to automatically detect DOS-like pathnames in filename arguments and change things like C:\ into /, or rearrange arguments for more complex DOS commands.

The benefit of doing it this way would be that you would still be able to use Unix shell commands alongside the DOS aliases, and you would also be able to use DOS commands in more complex compound shell commands constructs, if you would wish to.

Answer 3

Why not write a script that adds aliases to your .bashrc for those DOS commands and map the commands to the appropriate Bash counterpart. You could also make it so you could easily remove those entries with a script, so you could basically migrate your bash environment from computer to computer.

You could also make it so that it moves the original .bashrc to .bashrcbak and puts yours in place then when you want to revert just have it move the original back.

Or you could make single session aliases like found here: https://unix.stackexchange.com/a/148928/321418