App.use of the function of the regular expression/means what Nodejs pm2 how to install garbled how to solve

What is the role of App.use in the 1.express framework?

The manual reads:

App.use ([path], function) Use the given middleware function, with optional mount Path, defaulting to "/".

is to introduce a so-called middleware, is actually used to re- hack req and res objects before the actual request to achieve some functions, than if the simplest logger is to add a listener to the end event of the res write a log record, Express uses the middleware provided by Connect,

Next (); The program continues in order.

2. In regular expressions , where do the slashes "/" need to be escaped? What situations do not need to be escaped?  5

tests the regular expression. Sometimes,/this symbol needs \/to represent. Sometimes, /direct use is possible. No escaping. what situations need to be escaped?

normally /do not need to escape, unless you write JavaScript, because his patter is written "/..../", so the inside/need to escape.

only backslashes need to be escaped,/direct use can be used to use \, need to use \ \ to escape

3. How to install PM2

after installation, run pm2/pm2 list-bash pm2 command not found

NPM installed Nodejs need to manually establish a soft connection

and ln-s to/usr/local/bin.

PM2 List garbled

You can modify the format of the client encoding format to utf-8 .

App.use of the function of the regular expression/means what Nodejs pm2 how to install garbled how to solve