Comparing the floating numbers in scripts

eg integers
a1=11
b1=10
if [ $a1 -gt $b1 ] ; then
echo "greater"
else
echo "lesser"
fi

#working
----------------------------------------
eg float

a1=10.09
b1=10.07
if [ $a1 -gt $b1 ] ; then
echo "greater"
else
echo "lesser"
fi



# every time giving lesser

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So use bc to compare other than integer in if

a1=12.50
b1=11.01
ans=$(echo "$a1 > $b1" | bc)
if [ $ans -eq 1 ]; then
echo "Greater"
else
echo "lesser"
fi