脚本练习一：备份与删除

第一次练习，代码比较臃肿，主要就是用for循环来写的。
#!/bin/bash

while true
do
	echo "##############################"
	echo "#####      1 Copy       ######"
	echo "#####      2 Delete     ######"
	echo "#####      3 Quit       ######"
	echo "##############################"

	read -p "Please select you want to do: " num

	if [ $num -eq 1 ];then
		echo "You choose is:COPY"
		echo "**********************************************************"
		echo "*Note: the file name you entered can only is the current directory or the absolute path of files.*"
		echo "**********************************************************"
		
		read -p "Please enter your copy of the file or directory：" file
		if [ ! -e $file ];then
			echo "$file is not exist"
			echo "please input again: "
		continue
		fi
		
		read -p "Please enter a target directory: " dir
			if [ ! -e $dir ];then
				echo "$dir is not exist"
				echo "please input again: "
			continue
			fi
			if [ -f $dir ];then
				echo "$dir is a file,not a directory"
				echo "please input again: "
			continue
			fi
			if [ -d $dir ];then
				echo "Are you sure want to copy file to: $dir"
				echo "Yes! input 'y' "
				echo "No! input 'n'"
				read -n 1 keys
				if [ $keys == y ];then
					echo
					cp -a $file $dir
					if [  $? ];then
						echo "*******`date '+%Y-%m-%d %H:%M:%S'`*******"
						echo "Copy $file success"
						echo "*********************************"
						sleep 2
					else
						echo "Copy $file failed"
						sleep 2
					exit 13
					fi
				elif [ $keys == n ];then
					echo "Program exits"
                    sleep 2
					exit 14
				fi
			fi
	continue
	fi
	
	if [ $num -eq 2 ];then
		echo "You choose is:Delete"
		read -p "Please input you want to delete the target file directory：" dir_del
		if [ ! -e $dir_del ];then
			echo "$dir_del is not exist"
			echo "please input again! "
			continue
		elif [ -f $dir_del ];then
			echo "Input $dir_del is a file,Please enter the directory first"
			continue
		elif [ -d $dir_del ];then
			read -p "Please input you want to delete the target file_name: " file_del
			if [ ! -e $file_del ];then
				echo "$file_del is not exist"
				echo "please input again! "
				continue
			elif [ -d $file_del ];then
				echo "Input $file_del is a directory,Please enter a file"
				continue
			elif [ -f $file_del ];then
				echo "input 'y'"
				echo "input 'n'"
				echo
				read -n 1 keys_del
				if [ $keys_del == y ];then
					cd $dir_del
					rm -f $file_del 
					if [ $? ];then
						echo
						echo "*******`date '+%Y-%m-%d %H:%M:%S'`*******"
						echo "Delete file success!"
						echo "*********************************"
						sleep 2
					else
						echo "Delete file failed"
						sleep 2
						exit 15						
					fi
				elif [ $keys_del == n];then
					echo "Program exits"
                    sleep 2
					exit 16
				fi				
			fi
		fi
	continue
	fi
	
	if [ $num -eq 3 ];then
		exit
	fi
done