Linux Shell string interception and splicing

A string interception of Linux is useful. There are eight ways.

Suppose there is a variable var=http://www.linuxidc.com/123.htm

1 # 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.linuxidc.com/123.htm

.  

2 # # Intercept, delete the left character and 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.linuxidc.com/

The result is 123.htm.

3% Intercept, delete right character, leave left character

Echo ${var%/*}

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

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

4 -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:

5 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:

6 start 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.linuxidc.com/123.htm

7 starting 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: 123

8 start with 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)

A method of concatenation of strings in two Linux Shell scripts

If you want to add a character after a variable, you can use the following method:


$value 1=home


$value 2=${value1} "="


Echo $value 2


Add the string variable you want to add {}, and you need to put the $ out.


The result of this output is: home=, which means the connection was successful.


Another example:


[Email protected] sh]# var1=/etc/
[Email protected] sh]# var2=yum.repos.d/
[[email protected] sh]# var3=${var1}${var2}
[Email protected] sh]# echo $var 3
/etc/yum.repos.d/

Note: Reference connection: http://www.linuxidc.com/Linux/2015-03/115198.htm

Linux Shell string interception and splicing