bash脚本中的浮点数比较

Question

I tried to compare floating point number by -gt but it says that point expecting integer value. That means it can not handle floating point number . Then i tried the following code

chi_square=4
if [ "$chi_square>3.84" | bc ]
then
echo yes
else
echo no
fi

But the output is wrong with error . Here is the out put-

line 3: [: missing `]'
File ] is unavailable.
no

Here the no is echoed but it should be yes . I think that's because of the error it's showing. can anybody help me.

Answer 1

If you want to use bc use it like this:

if [[ $(bc -l <<< "$chi_square>3.84") -eq 1 ]]; then
   echo 'yes'
else
   echo 'no'
fi

Answer 2

Keep it simple, just use awk:

$ awk -v chi_square=4 'BEGIN{print (chi_square > 3.84 ? "yes" : "no")}'
yes

$ awk -v chi_square=3 'BEGIN{print (chi_square > 3.84 ? "yes" : "no")}'
no

or if you prefer avoiding ternary expressions for some reason (and also showing how to use a value stored in a shell variable):

$ chi_square=4
$ awk -v chi_square="$chi_square" 'BEGIN{
    if (chi_square > 3.84) {
        print "yes"
    }
    else {
        print "no"
    }
}'
yes

or:

$ echo "$chi_square" |
awk '{
    if ($0 > 3.84) {
        print "yes"
    }
    else {
        print "no"
    }
}'
yes

or to bring it full circle:

$ echo "$chi_square" | awk '{print ($0 > 3.84 ? "yes" : "no")}'
yes