bt3.sh

#!/bin/sh

_ls() { ls -la $1; }
_cat() { cat $@; }
_cd() { cd $1; }
_mkdir() { mkdir $1; }
_pwd() { pwd $1; }
_cp() { cp -r $1 $2; }
_exit() { exit $1; }

declare -A COMMANDS=(
	["cd"]=_cd
	["ls"]=_ls
	["cat"]=_cat
	["cd"]=_cd
	["mkdir"]=_mkdir
	["pwd"]=_pwd
	["cp"]=_cp
	["exit"]=_exit
)

main() {
	while :
	do
		echo -n "->>  "
		IFS=' ' read -ra array
		params=("${array[@]:1}")
		if [ ${#array} -eq 0 ]; then
			continue
		elif [ "${COMMANDS[${array[0]}]}" = "" ]; then
			echo "${array[0]} command not found"
		fi
		${COMMANDS[${array[0]}]} ${params[@]}
	done
}

main