有人可以在 bash 中解释这个 try/catch 替代方案吗？
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Could someone explain this try/catch alternative in bash?
提问by Harrys Kavan
So I found out that bash does not handle exceptions (there is no try/catch). For my script, I would like to know if a command was successful or not.
所以我发现 bash 不处理异常（没有 try/catch）。对于我的脚本，我想知道命令是否成功。
This is the part of my code right now:
这是我现在代码的一部分：
command = "scp -p$port $user:$password@$host:$from $to"
$command 2>/dev/null
if (( $? == 0 )); then
echo 'command was successful'
else
echo 'damn, there was an error'
fi
The things I don't understand are:
我不明白的事情是：
- line 3, why do I have to put the
2behind the$command? - line 5, what exactly is it with this
$?
- 第 3 行，为什么我必须把 放在
2后面$command？ - 第 5 行，这到底是
$怎么回事？
回答by legrandviking
$?means the return code of the last executed command.
$?表示上次执行命令的返回码。
2>means redirecting the stderr(standard error stream) output to /dev/null.
2>意味着将stderr（标准错误流）输出重定向到/dev/null.
回答by William
Just FYI, this will also work:
仅供参考，这也将起作用：
if some_command 2>/dev/null ; then
echo 'command was successful'
else
echo 'damn, there was an error'
fi
