如何在 bash for 循环中设置变量？
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How do I set a variable inside a bash for loop?
提问by Isaac Moore
I need to set a variable inside of a bash for loop, which for some reason, is not working for me. Here is an excerpt of my script:
我需要在 bash for 循环中设置一个变量，由于某种原因，这对我不起作用。这是我的脚本的摘录：
function unlockBoxAll
{
appdir=$(grep -i "CutTheRope.app" /tmp/App_list.tmp)
for lvl in {0..24}
key="UNLOCKED_$box_$lvl"
plutil -key "$key" -value "1" "$appdir/../Library/Preferences/com.chillingo.cuttherope.plist" 2>&1> /dev/null
successCheck=$(plutil -key "$key" "$appdir/../Library/Preferences/com.chillingo.cuttherope.plist")
if [ "$successCheck" -eq "1" ]; then
echo "Success! "
else
echo "Failed: Key is $successCheck "
fi
done
}
As you can see, I try to write to a variable inside the loop with:
如您所见，我尝试使用以下命令写入循环内的变量：
key="UNLOCKED_$box_$lvl"
But when I do that, I get this:
但是当我这样做时，我得到了这个：
/usr/bin/cutTheRope.sh: line 23: syntax error near unexpected token `key="UNLOCKED_$box_$lvl"'
/usr/bin/cutTheRope.sh: line 23: `key="UNLOCKED_$box_$lvl"'
What am I not doing right? Is there another way to do this?
我做错了什么？有没有其他方法可以做到这一点？
Please help, thanks.
请帮忙，谢谢。
回答by DVK
Use
用
for lvl in 1 2 3 4
do
key="UNLOCKED_${box}_$lvl"
done
You were missing "do"/"done" keywords wrapping around the loop body
$box_$lvlis treated by bash as a variable with the namebox_followed by variable with the namelvl. This is because_is a valid character in a variable name. To separate the variable name from following_, use${varname}syntax as shown above{0..24}does not work in bash v2 (which our servers have here) though it works as a range shortcut on modern bashso that should not cause youproblems.
您缺少环绕循环体的“do”/“done”关键字
$box_$lvlbash 将其视为名称box_后跟名称为 的变量的变量lvl。这是因为_是变量名中的有效字符。要将变量名称与以下内容分开_，请使用${varname}如上所示的语法{0..24}在 bash v2（我们的服务器在这里有）中不起作用，尽管它在现代 bash 上用作范围快捷方式，因此不会导致您出现问题。
