BASH 脚本使用输入和标准错误来长列表目录

Question

我想创建一个以长格式列出目录内容的脚本。但是，我想首先确保用户在提示之前不会将输入添加到脚本命令行，如果需要应用错误并退出。如果它通过了该测试，那么脚本应该在尝试列出它之前确保该目录存在。如果没有，则出现另一个错误。如果存在，我需要在长列表中显示内容。

我在这方面真的很陌生，这就是我目前所拥有的。我不确定我是否走在正确的轨道上。任何帮助将不胜感激。

#!/bin/bash

# File Name: dlist
# Usage: dlist prompt: [/directory/path/here]
# Synopsis: The dlist script will prompt the user to input a directory path and will 
# return a long listing of the contents in that directory.
# Author: Romero

# Notify user of incoming prompt
echo -e "You will be prompted to enter the name of a directory you want to list in long form. "
# Prompt the user to input the directory to list on the same line as the input prompt
read -p "Directory to list: "
# Ensure User has not input directly into command line; if so issue std error 1 and exit

# Check to ensure directory exists before listing; if not issue std error 2 and exit
# If directory exists, list it in long form
if [ ! -d "$DIRECTORY" ]; then
     echo "This directory does not exist to list!" 1>&2
     exit 2
elif [ -d "$DIRECTORY" ]; then
     echo ls -l "$DIRECTORY"
fi 

Answer 1

使用 Bash 变量 $# 来获取参数的数量。示例见here。