IP to Integer and Integer to IP conversions in bash.

itoa.sh

#Handy functions for .bashrc loading.
#
# $ atoi 192.168.1.1
# 3232235777
# $ itoa 3232235777
# 192.168.1.1


function atoi
{
#Returns the integer representation of an IP arg, passed in ascii dotted-decimal notation (x.x.x.x)
IP=$1; IPNUM=0
for (( i=0 ; i<4 ; ++i )); do
((IPNUM+=${IP%%.*}*$((256**$((3-${i}))))))
IP=${IP#*.}
done
echo $IPNUM 
} 

function itoa
{
#returns the dotted-decimal ascii form of an IP arg passed in integer format
echo -n $(($(($(($((${1}/256))/256))/256))%256)).
echo -n $(($(($((${1}/256))/256))%256)).
echo -n $(($((${1}/256))%256)).
echo $((${1}%256)) 
}