htmlifelse語句例子？

#ifelse_exam.sh腳本用于檢查輸入的字符串是否是一個當前目錄

#!/bin/bash

if [ "$1" ]

then

echo "What you input is not null"

if [ -e "$1" ]

then

echo "The file $1 is existence!"

else

echo "The file $1 is not existence!"

fi

else

echo "What you input is null!"

fi