Originally published at: https://www.cyberciti.biz/tips/linux-unix-get-yesterdays-tomorrows-date.html
When invoked without arguments, the date command displays the current date and time. Depending on the options specified, the date would set the date and time or print it in a user-defined format. However, how do you get yesterdays with bash? What about tomorrows day? I have seen many sysadmins writing Perl scripts for calculating relative dates such as yesterdays or tomorrows day. You can use the GNU , which is designed to handle relative date calculation such as: