This post is older than a year. Consider some information might not be accurate anymore.
I got some bash scripts handed out and saw that some variables are referenced like that
echo ${var}
Scratching my head, why I should write it like that, since the straightforward way will also work.
echo $var
I found a good answer: What is the difference between ${var}, β$varβ, and β${var}β in the Bash shell?