Bash technique: execute multiple commands concurrently in the script and wait for the command execution to finish
In Bash, you can use control operators&Let the command run in the background, and then use thewaitThe built-in command waits for the task to complete. Control operator& See man bash for control...
![[20191126] explore the origin of waiting event 2.txt](http://89d09a84-dbc3-4e4a-9e81-06f1feac0ad0/icons/logo.png){kind=icon}
Promise and generator
The callback to hell in JS is an extremely painful thing. Promise can be a better solution, but it also has disadvantages. Let’s talk about its basic usage first.If we do not use promise to write asynchronous operations, suppose we request three files: 1.txt;2.txt;3.txt In JS, we will write as follows: $.ajax({ url('./upload/1.txt'), success(data) { //do something ...