Check for IP Address changes on my Raspberry Pi

manager Tue, 02/10/2026 - 19:01

Script that is called from Cron

cat /home/pi/send_ip.sh

#!/bin/bash
echo -n "$(date '+%Y-%m-%d %H:%M') "
hostname -I | awk '{for(i=1;i<=NF;i++) if ($i ~ /^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$/) printf "%s ", $i; print ""}'

Run this in Cron

$ crontab -e
# +---------------- minute (0 - 59)
# |  +------------- hour (0 - 23)
# |  |  +---------- day of month (1 - 31)
# |  |  |  +------- month (1 - 12)
# |  |  |  |  +---- day of week (0 - 6) (Sunday=0)
# |  |  |  |  |
# *  *  *  *  *  command to be executed
#  0 8  *  *  * /opt/scripts/down.sh >> /home/pi/log/shade.log 2>&1
#  0 11  *  *  * /opt/scripts/up.sh >> /home/pi/log/shade.log 2>&1
1 7 * * * /home/pi/send_ip.sh | ssh shade@server "cat >> /home/shade/log/shade.log" 2>> /home/pi/cron_debug.log

Show the file on the server that logs the IP address each day

ls -l /home/shade/log
total 4
-rw-rw-rw- 1 shade shade 2519 Sep 19 07:40 shade.log

Show the contents of the shade.log file

$ cat shade.log

# log file for host IP of shade Raspberry Pi  Started out as 192.168.1.118 Jun 9, 2025

2025-06-09 20:01 192.168.1.118
2025-06-10 07:01 192.168.1.118
2025-06-11 07:01 192.168.1.118

Get Internal and External IP and date and time

#!/bin/bash 

# 1. Get Public IP (with a break so it doesn't overwrite a success) 
SERVICES=("https://ifconfig.me" "https://api.ipify.org" "https://icanhazip.com") 
Ext_IP="Public IP: Not Found" 
for url in "${SERVICES[@]}"; do 
    PUBLIC_IP=$(curl -s --max-time 5 "$url") 
    if [ -n "$PUBLIC_IP" ]; then 
        Ext_IP="Public IP: $PUBLIC_IP" 
        break # Important: Stop looking once we find one! 
    fi 
done 

# 2. Get Internal IP and strip the trailing newline 
# We use 'tr -d "\n"' to ensure it stays on the same line 
INT_IP=$(hostname -I | awk '{for(i=1;i<=NF;i++) if ($i ~ /^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$/) printf "%s ", $i}' | tr -d '\n') 

# 3. Output everything at once 
echo "$(date '+%Y-%m-%d %H:%M') | Int_IP: $INT_IP | $Ext_IP"