bash - Floating point comparison in shell

Question

Can you please suggest to me the syntax for doing floating point comparison in a Bash script? I would ideally like to use it as part of an if statement. Here is a small code snippet :

key1="12.3"
result="12.2"

if (( $result <= $key1 ))
then
    # some code here
fi

Answer 1

bc is your friend:

key1="12.3"
result="12.2"
if [ $(bc <<< "$result <= $key1") -eq 1 ]
    then
    # some code here
fi

Note the somewhat obscure here string (<<<) notation, as a nice alternative to echo "$result <= $key1" | bc.

Also, the un-bash-like bc prints 1 for true and 0 for false.