My work machine changes IP, If I want to ssh into it from home, often I need to know its ip. This is the bash script to report ip change to my slack. Need to set cron job: crontab -e, 0 * * * * /home/xxx/reportip.sh

reportip.sh

#!/bin/bash

touch oldIp.txt

md1=$(cat "oldIp.txt");
md2=$(hostname -I);

if [ "$md1" = "$md2" ]; then
  echo The same
else
  echo Different
  hostname -I
  cat oldIp.txt
  hostname=$(hostname);
  echo "{\"text\":\"ip of ${hostname} is ${md2}\"}" | curl -X POST -H 'Content-type: application/json' --data @- https://hooks.slack.com/services/xxx/xxx/xxx
  hostname -I > oldIp.txt
fi