Unix How-To: Quotes to Live By

“One of the things that really throws new Unix users is when to
use quotes and which kind of quotes. Between single quotes, double
quotes and back ticks, a person can start to feel that Unix is
unnecessarily tricky.

“Double quotes are the easiest to understand. Unlike Windows,
the only way to work on the command line with files whose names
contain blanks (e.g., “my file”) is to enclose the file names in
some kind of quotes. If you want to echo text to a user containing
strings of consecutive blanks (e.g., “first second”), you need the
quotes, else you get “first second”.”

Complete Story