Linux – Days since a specific date

bashlinuxmac-osxterminalunix

How to print in linux/unix bash the number of days since a specific date till now? (for example days since 23rd of June 2009 till today)!

You can use something like this:

date1=$(date --utc --date "2008-10-20" +%s)
date2=$(date --utc --date "2009-10-20" +%s)
diffdays=$(( (date2-date1)/(3600*24) ))

This assumes date2 is more recent than date1.

Use screen, a free terminal multiplexer developed by the GNU Project that will allow you to have several terminals in one.

You can start a session and your terminals will be saved even when you connection is lost, so you can resume later or from home.

You can just use executable faketime (from ubuntu repositories sudo apt-get install faketime) by:

faketime -f "-15d" date

Or even fake time in whole shell by

faketime -f "-15d" bash -l