bash 比较bash中的负数
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Compare negative numbers in bash
提问by Davidiusdadi
How can i accomplish number comparison involving negative numbers?
如何完成涉及负数的数字比较？
if [[ "-2" > "-1" ]]; then
echo "-2 >-1"
else
echo "-2 <=-1"
fi
I also tried
我也试过
if [ '-2' -lt '-1' ]; then
but the condition always behaves as if -2 would be greater than -1.
但条件总是表现为 -2 将大于 -1。
The comparisons work when i do not use negative numbers.
当我不使用负数时，比较有效。
I would like a solution in pure bash if possible.
如果可能的话，我想要一个纯 bash 的解决方案。
回答by devnull
Seems to work correctly:
似乎工作正常：
if [[ "-2" -gt "-1" ]]; then
echo "-2 >-1"
else
echo "-2 <=-1"
fi
Output:
输出：
-2 <=-1
You might want to use ((...))which enables the expression to be evaluated according to rules of Shell Arithmetic.
您可能希望使用((...))which 使表达式能够根据 Shell 算术规则进行计算。
$ ((-2 <= -1)) && echo Smaller or equal || echo Larger
Smaller or equal
$ ((-2 <= -3)) && echo Smaller or equal || echo Larger
Larger
回答by Karoly Horvath
-ltmeans less than. And indeed, -2 is less than -1.
-lt表示小于。事实上，-2 小于 -1。
Your want to use -gt, greater than.
你要使用-gt，大于。
回答by fedorqui 'SO stop harming'
$ a=-2
$ [ $a -le -1 ] && echo "i am lower or equal than -1"
i am lower or equal than -1
or
或者
if [ $a -le -1 ]; then
echo "i am lower or equal than -1"
fi
To make it "greater than", you need ge(greater or equal) or gt(strictly greater than).
要使其“大于”，您需要ge（大于或等于）或gt（严格大于）。
