shell - 验证复制成功

Question

我想编写一个脚本来验证复制是否成功。
这是我所拥有的:

#!/bin/sh
cp home/testing/present.txt home/testing/future.txt
   echo "Copy Code: $? - Successful"
if [ $? != 0 ]; then
   echo "Copy Code: $? - Unsuccessful"
fi

“if”语句没有被初始化。如何解决这个问题？
感谢您的时间。

Answer 1

$?指的是最后一条命令:

#!/bin/sh
cp home/testing/present.txt home/testing/future.txt
   echo "Copy Code: $? - Successful"   # last command: cp
if [ $? != 0 ]; then                   # last command: echo
   echo "Copy Code: $? - Unsuccessful" # last command: [
fi

如果要重复处理特定命令的状态，只需将结果保存在另一个变量中:

#!/bin/sh
cp home/testing/present.txt home/testing/future.txt
status=$?
echo "Copy Code: $status - Successful"
if [ $status != 0 ]; then
   echo "Copy Code: $status - Unsuccessful"
fi

但是，更好的方法是简单地测试 cp首先命令:

if cp home/testing/present.txt home/testing/future.txt
then
  echo "Success"
else
  echo "Failure, exit status $?"
fi