bash script to unblock IP from iptables and denyhosts

unblockip.sh

#!/bin/bash 
 
# Check if an IP address is provided 
if [ -z "$1" ]; then 
    echo "Usage: $0 <IP>" 
    exit 1 
fi 
 
# Check if the provided argument is a valid IP address 
if ! echo "$1" | grep -Pq '^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$'; then 
    echo "Invalid IP address: $1" 
    exit 1 
fi 
 
# Unblock an IP address from denyhosts and iptables 
 
IP=$1 
 
# Check if IP is blocked in denyhosts 
denyhosts_blocked=$(grep -l $IP /var/lib/denyhosts/* /etc/hosts.deny) 
 
# Check if IP is blocked in iptables 
iptables_blocked=$(iptables -L INPUT -v -n | grep $IP) 
 
if [ -z "$denyhosts_blocked" ] && [ -z "$iptables_blocked" ]; then 
    echo "IP $IP is not blocked. Exiting." 
    exit 0 
fi 
 
echo "IP $IP is blocked. Unblocking..." 
 
/etc/init.d/denyhosts stop 
for f in /var/lib/denyhosts/* /etc/hosts.deny ; do  
    grep -v $IP $f > tmp 
    mv tmp $f  
done 
 
# Loop over iptables rules and remove all instances of the IP 
while iptables -D INPUT -s $IP -j DROP 2> /dev/null; do 
    echo "Removed iptables rule for IP $IP" 
done 
 
/etc/init.d/denyhosts start 
 
echo "IP $IP has been unblocked."