Regular matching starts with what, ends with what, starts with what, and ends with what

What does regular matching begin with 、 What does it end with , Start with something other than , End with something else

（1） Regular match to start Starting string

^(?=start)

（2） Regular matching with non start Starting string .

^(?!start)

（3） Regular match to end Ending string .

(?<=end)$

（4） Regular matching with non end Ending string .

(?<!end)$

logstash Of grok Extract the data after the keyword in brackets to the specified field _zhangphil The blog of -CSDN Blog logstash Of grok Extract the data after the bracketed keyword to the specified field, such as , Now there is a piece of data , Need to extract [TASKID:***] Inside * data , That is, the 1a-2b_3c , Then put it in the specified field task_id Inside . stay grok It says regular ： stay grok debugger Run inside ： summary ：...https://blog.csdn.net/zhangphil/article/details/125172132