"In Bash, whether to use single or double quotes depends on
exactly what you want to do, and the differences can trip you up if
you're not concentrating. Here's a quick rundown of what each does
and when to use them.
"Double quotes are the less restrictive option. Within a
double-quoted string, the only special characters that are
reinterpreted are $, ` (backquote), and (the escape character).
Double quotes are useful when using variables (in case the variable
uses other special characters), or to avoid whitespace being used
to make one argument into two. For example:"