Shell script 8 Methods of string interception _linux shell

The string interception of Linux is useful. There are eight different ways.

Suppose there are variable var=http://www.aaa.com/123.htm.

1. # Intercept, delete left character, keep right character.

Copy Code code as follows:

Echo ${var#*//}

where Var is the variable name, # is the operator, and *//indicates that the first//number and all characters on the left are deleted from the left
That is, delete http://
The result: www.aaa.com/123.htm

2. # # Intercept, delete left character, keep right character.

Copy Code code as follows:

Echo ${var##*/}

##*/indicates that the last (rightmost) one/number and all characters on the left are deleted from the left.
That is, delete http://www.aaa.com/

The result is 123.htm.

3.% Intercept, remove the right character, leave the left character

Copy Code code as follows:

Echo ${var%/*}

%/*, starting from the right, deletes the first/number and the right character

The result: http://www.aaa.com

4.%-percent intercept, delete the right character, leave the left character

Copy Code code as follows:

Echo ${var%%/*}

%%/*, starting from the right, deletes the last (leftmost) one/number and the right character
The result: http:

5. Starting with the first few characters on the left and the number of characters

Copy Code code as follows:

Echo ${var:0:5}

0 represents the beginning of the first character on the left, and 5 represents the total number of characters.
The result: http:

6. Start with the first few characters on the left, until the end.

Copy Code code as follows:

Echo ${var:7}

7 of these represent the beginning of the 8th character on the left, until the end.
The result: www.aaa.com/123.htm

7. Starting with the first few characters on the right and the number of characters

Copy Code code as follows:

Echo ${var:0-7:3}

0-7 of these represent the start of the seventh character on the right, and 3 for the number of characters.
The result: 123

8. Start with the first few characters on the right, until the end.

Copy Code code as follows:

Echo ${var:0-7}

Represents the beginning of the seventh character on the right, until the end.
The result: 123.htm

Note: (The first character on the left is represented by 0, and the first character on the right is represented by 0-1).