I am creating a simple backup script. I would like to have a message saying You last backed up x days ago on login. I can create a file when I do the backup backup/.last_backup_timestamp but what format should I use and how would I find the difference in days between then and now in bash?Thank-you
How do I get the difference between two timestamps?
bash;scripting;timestamps
You can use the date utility to write the timestamp of a file, and the current time, as seconds elapsed from the Epoch, then format a string to convert the seconds of the difference in days with bc:echo scale=2; ($(date +%s)-$(date -r file +%s)) / (3600 * 24) \  | bc