What is the method for extracting a string in Linux?

In the Linux system, you can extract strings using the following method:

1. Using variable assignment truncation: The truncation function of variables can be used to extract a part of a string. For example, if there is a string variable str=”Hello World”, you can use the following command to truncate a part of the string:
2. Output the substring of ‘str’ starting at index 6 and with a length of 5 characters.
3. This will output “World”, where 6 represents starting from the 6th character and 5 represents the length to be extracted.
4. With the sed command, which is a stream editor, text can be manipulated. Regular expressions can be used with sed to extract strings. For example, if we have a string “Hello World” and want to extract the “World” part, we can use the following command:
5. Print “Hello World” with the “Hello” removed.
6. This will output “World” where \1 represents the first substring matched by the regular expression.
7. The cut command is used to extract fields from a file or standard input. The -d parameter specifies the field delimiter, and the -f parameter specifies the field to extract. For example, to extract the “World” part from the string “Hello World”, you can use the following command:
8. Print the second word from the phrase “Hello World”.
9. This will output “World”, where -d’ ‘ represents using a space as the field delimiter, and -f2 represents extracting the second field.

These are common methods for extracting strings in Linux systems, choose the one that suits your specific situation.