在bash比较数字 [英] Comparing numbers in bash

问题描述

我开始了解这场舞会终端编写脚本，但我不能工作了如何让比较正常工作。我敢肯定，这是很基本的许多你我似乎无法在别处找到了答案，我的问题（或至少我不能完全确定该怎么寻找）。我使用的脚本是：

I'm starting to learn about writing scripts for the bash terminal, but I can't work out how to get the comparisons to work properly. I'm sure this is very basic to many of you I just can't seem to find the answer to my question anywhere (or at least I'm not totally sure what to search for). The script I'm using is:

echo "enter two numbers";

read a b;

echo "a=$a";
echo "b=$b";

if [ $a \> $b ];
then 
    echo "a is greater than b";
else
    echo "b is greater than a";
fi;

我的问题是，它的数目，从所述第一数字进行比较，即，图9是大于10000大，但1大于09如何可以转换的数字成型做一个真比较？我意识到，这可能是不快简单，但任何帮助将大大AP preciated！

The problem I have is that it compares the number from the first digit on, i.e. 9 is bigger than 10000, but 1 is greater than 09. How can I convert the numbers into a type to do a true comparison? I realise that this is probably irritatingly simple, but any help would be greatly appreciated!

推荐答案

在bash中，你应该做你的支票算术上下文：

In bash, you should do your check in arithmetic context:

if (( a > b )); then
    ...
fi

对于不支持POSIX弹（（）），您可以使用 -lt 和 -gt 。

if [ "$a" -gt "$b" ]; then
    ...
fi

您可以得到比较运营商的完整列表，以帮助测试。

You can get a full list of comparison operators with help test.

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