[hawski]

Wouldn't "cat $today" result with "cat: No such file or directory: 2019-01-08"? Did you mean echo instead of cat?

[flukus]

My real life use case for these dynamic variables would be more like "cat/vim/cp $log" to get today's log file which would expand to something like /somedir/logs/201901/09/product.log. Handy when you have a large matrix of products/environments.

[forty]

Only in the case when no such file exists in the current directory :)