Bash can handle getting integer from float very easily:

[root@i ~]# cat ./f_to_i.sh
#!/bin/bash

f=20.3
i=${f%.*}

echo "float: " $f
echo "integer: " $i
[root@i ~]#

[root@i ~]# bash ./f_to_i.sh
float: 20.3
integer: 20
[root@i ~]#