21 special symbols in Linux

 

21 special symbols in Linux

1.> redirect output symbols. 2.> the redirection output symbol, but the append function is available. 3. 2> the error redirection output symbol overwrites the content of the original file. 4. 2> error redirection output symbol, with the file content appending function. 5. * match any character. 6 .? Match any character. 7. | MPs queue symbol. 8. & background process identifier. 9. & L logic and symbols. Usage: command 1 & command 2 indicates that if command 1 is successfully executed, continue to execute command 2. 10. | logic or symbol. Usage: command 1 | command 2 indicates that if command 1 is successfully executed, command 2 is not executed. If command 1 fails, command 2 is executed. 11. Logical unsigned. Exclude the specified range. 12. [x-y] indicates a certain range. 13. # annotator. 14. "" Double quotation marks indicate that the content contained in it is a common character, except for the symbols ''' $. 15. ''single quotes indicate that the content contained in it is a common character without special exceptions. 16. $ variable. 17./escape characters. 18. ''indicates the content contained in it. 19.; command separator. 20. <redirect input character. 21. () indicates the overall command execution.