下面两个将内容从一个目录复制到另一个目录的程序有什么区别？

Question

程序编号 1（出现错误）

#!/bin/bash

echo "Enter source and destination directories: "
read $src $dest

if  [ -d $src ]  &&  [ -d $dest ]
then 
  echo "Process will start "
 else 
   echo "Enter valid directories"
   exit 1
 fi

 cp -r $src $dest

 status=$?

 if  [ $? -eq 0 ]
 then 
   echo "Successfully completed "

  else 
    echo "facing some problems "
fi 

---

第二个程序（执行时没有出现任何错误）

#!/bin/bash

echo "Enter Sourse Directory name : "

read src

echo "Enter destination directory: "

read dest

 if [ ! -d $src ]
    then 
    echo "Enter Valid Directory name "
    exit 1
elif [ ! -d $dest ]
     then
     echo "Enter Valid Destination source name "
      exit 2
fi 

cp -r $src $dest 

status=$?

if [ $status -eq 0 ]
then 
echo "File copied succesfully"
else 
echo "there is a problem"
fi

Answer 1

一个巨大的差异就在你的眼前：

方案一：

read $src $dest

方案2：

read src
[...]
read dst

read是一个 shell 内置函数（参见联机帮助页）提供的变量名称必须不是首先$