The back quotes in Unix

I was trying out this great script to make backups: thanks to Julius’ blog

I realised that there was a line:

date_daily=`date +"%d-%m-%Y"`

with the back quote `

Ok. I thought it could have been a problem of cut&paste because I have not come across this quote in other programming languages I use (ruby, javascript, php). But after a quick search I learnt that it is used to execute commands.

I learnt it here: