How to use quotation marks in Shell

1. Shell uses quotation marks (single quotation marks/double quotation marks) and backslash ("\") for the shell interpreterSHIELD special characters.

Reverse quotation marks [H2] have special significance for shell.

1.1 single quotes and backlash [H1] can prevent shell from being substituted into variable values;

1.2 double quotation marks cannot prevent substitution

For example:

Sles10i32-1: Han $ person = Han

Sles10i32-1: Han $ echo $ person

Han

Sles10i32-1: Han $ echo "$ person"

Han

Sles10i32-1: Han $ echo '$ person'

$ Person

Sles10i32-1: Han $ echo \ $ person

$ Person

2. Like single quotes, The backslash can also block all special characters. However, it can only block one character at a time, rather than a group of characters.
3. The anti-quotation mark function is different from the above three symbols. It does not have the function of shielding special characters. However, you can pass the running result of a command to another command.

Example:

Sles10i32-1: Han $ PWD.

/Users/Han

Sles10i32-1: Han $ echo 'pwd'

/Users/Han

[H1] The backslash can only block one character

[H2] in the upper left corner of the keyboard, and ~ Public a key.