Multiple ways to intercept shell script strings

The first four methods are to remove some characters, and the last four methods to preserve certain characters

1, # Intercept, delete the left character, retain the right character

var= "Hello World"
Echo ${var#*l}
Results:
Lo World

where Var is the variable name and the # is an operator, *l means that all characters from the first L and the left are deleted from the left.
that is, delete hel

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

var= "Hello World"
Echo ${var##*l}
Results:
D

##*l indicates that the last (rightmost) one L and all characters on the left are deleted from the left.
That is, delete Hello Worl

3,% number intercept, delete the right character, leave the left character

var= "Hello World"
Echo ${var%l*}
Results:
Hello Wor

%l* indicates that the first L and the right character are deleted from the right.

That is, delete D

4, the percent of the interception, delete the right character, the left character remains

var= "Hello World"
Echo ${var%%l*}
Results:
He

%%l* indicates that the last (leftmost) one L and right character is deleted from the right.

That is, delete Llo world

5, starting from the first few characters on the left, and the number of characters

var= "Hello World"
Echo ${var:0:3}
Results:
Hel

0 represents the first character on the left and 3 indicates the total number of characters.

6, starting from the first few characters on the left, until the end.

var= "Hello World"
Echo ${var:2}
Results:
Llo World

2 means that the 3rd character on the left begins, until the end.

7, starting from the right of the first few characters, and the number of characters

var= "Hello World"
Echo ${var:0-2:3}
Results:
Ld

0-2 means the second character starts at the right, and 3 indicates the number of characters.

8, starting from the first few characters on the right, until the end.

var= "Hello World"
Echo ${var:0-2}
Results:
Ld

Indicates that the second character from the right begins, until the end.

1 #!/bin/bash 2 var= "Hello World" 3 Echo ${var#*l} 4 echo ${var##*l} 5 echo ${var%l*} 6 echo ${var%%l*} 7 echo ${var : 0:3} 8 echo ${var:2} 9 echo ${var:0-2:3} Ten echo ${var:0-2}[[email protected] test6_16]$./string.sh Lo Worlddhello wor Hehelllo WORLDLDLD

This article is from the "Small Town Moss" blog, please make sure to keep this source http://fengbaoli.blog.51cto.com/10538178/1790049

Multiple ways to intercept shell script strings