String manipulation in the shell

String in Shell: string is the most commonly used and most useful data type in shell programming (in addition to numbers and strings, no other type is easy to use, haha), strings can be in single quotes, or double quotes, or without quotes. The difference between single and double quotes is similar to PHP.

Single quotes:

• Any character in a single quotation mark is output as is, and the variable in the single-quote string is invalid

• Single quotation marks cannot appear in single quote string (not after using escape character for single quotes)

Double quotes:

• You can have variables in double quotes.

• Escape characters can appear in double quotes

1. Stitching strings

Your_name= "QINJX" greeting= "Hello," $your _name "!" greeting_1= "Hello, ${your_name}!" echo $greeting $greeting _12, get string length: string= "ABCD" Echo ${#string} #输出: 4 explanation: The # number is used to get the string length 3, extract the substring string= "Alibaba is a Great company "Echo ${string:1:4} #输出: Liba explanation: String:1:4 represents a string of strings, starting at position 1, intercepting 4 characters in length, string numbering starting from 0, left to right, once for 0,1,2 ... 4. Find substring string= "Alibaba is a great company" Echo ' Expr index "$string" is "#输出: 3, this statement means: Find out the position of the first character in the string

This article is from the "Linux Enthusiasts" blog, please be sure to keep this source http://5975954.blog.51cto.com/5965954/1642019

String manipulation in the shell