Single and double quotation marks in the shell

Use directly after declaring variables in the shell:

#！ /bin/bash

Na=zhagnsan

ag=11

Echo ' $na is $ag years old '

Output: $na is $ag years old

echo "$na is $ag years-old"

Output: Zhagnsan is one years old

Therefore, use "" in shell scripts to output variables and text.

Do not use the dollar sign when referencing a variable value in the shell to add the dollar character $, while referencing the variable to assign it.

eg

value=10

value2= $value

Echo $value 2

10

Single and double quotation marks in the shell