Question

if [ 3 -lt 6 ]; then
  echo "It works with ints"
fi

if [ 3.0 -lt 6.0 ]; then
  echo "It works with floats"
else
  echo "It doesn't work with floats"
fi

Comparing the integers in an "if" works just fine.

But it doesn't work when I do the same thing with floating point numbers, and gives me this output:

+ [ 3.0 -lt 6.0 ]
/tmp/hudson7259224562322746826.sh: 11: [: Illegal number: 3.0
+ echo It doesn't work with floats
It doesn't work with floats

Answer 1

根据bash联机帮助页（我最后的重点）：

arg1 OP arg2：OP是-eq，-ne，-lt，-le，-gt或{{}之一1}}。如果-ge分别等于，不等于，小于，小于或等于，大于或大于或等于arg1，则这些算术二元运算符返回true。 arg2和Arg1 可能是正整数或负整数。

换句话说，arg2在比较浮点值时没有原生支持。

如果您真的想要处理浮点数，那么最好选择支持它的工具，例如bash：

bc

Illegal Number when Comparing floats

1 个答案: