String interception of Linux shell scripts

Suppose there are variables var=http://www.hao.com/123.htm  

One, # Intercept, delete the left character, retain the right character.  

Echo ${var#*//}

where Var is the variable name, # is the operator, *//  deletes all characters from the first//number and to the left, starting from the left

that is, delete / http

The result is: www.hao.com/123.htm

Second, the # # Intercept, delete the left character, retain the right character.

Echo ${var##*/}

##*/  indicates that the last (rightmost) one/number and all characters to the left are deleted from the left.

that is, delete http://www.hao.com/

The result is 123.htm.

.  

Third,% intercept, delete the right character, leave the left character

Echo ${var%/*}

%/* indicates that the first/second and right characters are deleted from the right.

The result is: http://www.hao.com

Four, percent intercept, delete right character, leave left character

Echo ${var%%/*}

%%/* indicates that the last (leftmost) one/number and right character are deleted from the right.

The result is:http:  

Start with the first few characters on the left and the number of characters

Echo ${var:0:5}

0 represents the first character on the left and 5 indicates the total number of characters.

The result is:http:

.

Six, starting from the first few characters on the left, until the end

Echo ${var:7}

7 means that the 8th character on the left begins, until the end.

The result is:www.hao.com/123.htm

Seven , starting with the first character on the right, and the number of characters

Echo ${var:0-7:3}

one of the 0-7 indicates that the seventh character starts at the right, and 3 indicates the number of characters.

The result is: 123

Eight, starting from the first few characters on the right, until the end

Echo ${var:0-7}

The expression starts at the seventh character on the right and continues to the end.

Result is: 123.htm

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

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String interception of Linux shell scripts