http://www.linuxquestions.org/questions/programming-9/how-can-i-compare-floating-number-in-a-shell-script-336772/

gistfile1.txt

Just in case anyone is directed to this page, rather than doing some horribly convoluted solution, the following will work on most systems (even ones that dont have bc and perl) - eg many small devices running busybox.

As ahh said - 'awk' is probably your best friend here:

# Return the value of an operation
float_val() {
     echo | awk 'END { print '"$1"'; }'
}


Or more usefully:

# Return status code of a comparison
float_test() {
     echo | awk 'END { exit ( !( '"$1"')); }'
}

Note you have to invert it as exit(0) = success.


Full Example:

$ cat q.sh
# Float comparison eg float '1.2 > 1.3'

# Return the value of an operation
float_val() {
     echo | awk 'END { print '"$1"'; }'
}

# Return status code of a comparison
float_test() {
     echo | awk 'END { exit ( !( '"$1"')); }'
}


##########################################


x=1.2
y=1.02
float_test "$x > $y" && echo "$x > $y"

float_test "$x < $y" && echo "$x < $y"

z=`float_val "$x + $y"`

echo "$x + $y = $z"

z=`float_val "$x - $y"`

echo "$x - $y = $z"


Output:

$ sh q.sh
1.2 > 1.02
1.2 + 1.02 = 2.22
1.2 - 1.02 = 0.18