Single quotes:What you can say is what you see is what you get: the contents of a single quotation mark are output as-is, or what you see in single quotes is what you output. double quotes:The contents of the double quotation marks are output, and if there are commands, variables, etc., the variables, commands are parsed out and then the final content is output. No quotes:does not consider the string containing the space as a whole output, if the content has commands, variables, etc., will first parse the variables, commands, and then in the output of the final content, if the string with a space and other special characters, it will not be complete output, need to add double quotation marks, general continuous string, number, Paths, etc. can be used.
Describe simple differences between single quotes, double quotes, and unquoted in a Linux shell (2 minutes)
