Floating point comparison in shell

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

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.

bash doesn't do floats, use awk

key1=12.3
result=12.5
var=$(awk 'BEGIN{ print "'$key1'"<"'$result'" }')    
# or var=$(awk -v key=$key1 -v result=$result 'BEGIN{print result<key?1:0}')
# or var=$(awk 'BEGIN{print "'$result'"<"'$key1'"?1:0}')
# or 
if [ "$var" -eq 1 ];then
  echo "do something"
else
  echo "result more than key"
fi

there are other shells that can do floats, like zsh or ksh, you might like to try using them as well

another simple clear way with bc is this:

if ((`bc <<< "10.21>12.22"`)); then echo "true"; else echo "false"; fi