How to compare decimal values in bash?

Shell Programming and Scripting
1

Hi,

I am facing some error while doing the comparision between 2 decimal values in bash. Pl help me out.

I have tried using below scripts. But its giving me error.

1)

amt=12.3 opn_amt=12.5 var=$(awk 'BEGIN{ print "'$amt'"<"'$opn_amt'" }')    

if [ "$var" -eq 1 ];then   echo "correct" else   echo "Wrong" fi

2)Tried using bc also as follows , but no resolution.

amt="12.3" opn_amt="12.2" if [ $(bc <<< "$amt <= $opn_amt") -eq 1 ]     then  
 echo "correct" else   echo "Wrong" fi

Thanks
Sibadatta

2

A number of semicolons were missing, try:

amt="12.3" opn_amt="12.4"; if [ $(bc <<< "$amt <= $opn_amt") -eq 1 ]; then echo "correct"; else echo "Wrong" ; fi

You can avoid this and improve readability by using more lines:

amt="12.3" opn_amt="12.2"
if [ $(bc <<< "$amt <= $opn_amt") -eq 1 ]; then
  echo "correct"
else
  echo "Wrong" 
fi
3

Just another way

if [  $(echo $amt - $opn_amt | bc | grep ^-) ]; then
  echo "correct"
else
  echo "Wrong" 
fi
4

It should be noted that all of these examples are using the external bc utility, because BASH itself -- and most bourne shells except ksh -- do not support floating-point numbers.