Reproduced String interception of Linux shell scripts

Suppose there is a variable var=http://www.google.com/test.htm

A # Intercept, delete the left character, and leave the right character.
Echo ${var#*//}
where Var is the variable name and the # is an operator, *//indicates that the first//number and all characters on the left are deleted from the left.
Delete http://
The result is:www.google.com/test.htm

Two # # Intercept, delete the left character, leave 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.google.com/
The result is test.htm.

Triple 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.google.com

Four-percent intercept, delete the right character, leave the 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 starts with 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.google.com/test.htm

Seven starts with the first character on the right and the number of characters
Echo ${var:0-7:3}
0-7 means that the seventh character starts at the right, and 3 indicates the number of characters.
The result is: test

Eight starts from the first character 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.
The result is: test.htm

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

Original link: http://www.cnblogs.com/wangbin/archive/2011/10/11/2207179.html

Reproduced String interception of Linux shell scripts