Document other shell variable for debuging express

[zombieleet]

Specified DEBUG_FD and DEBUG_COLORS shell variables to handle redirection of logs to a file and enabling/disabling color output respectively

[wesleytodd]

Hi @zombieleet, thanks for the addition! Can you talk about why it requires re-asigning the FD to put debug out into a file? This will redirect only debug output, but wont most people be alright with just normal piping to file $ DEBUG=express:* node index.js > log.txt? Just thinking about keeping the docs simple :)

[zombieleet]

@wesleytodd $ DEBUG=express:* node index.js > log.txt does not send the DEBUG output to log.txt

[wesleytodd]

Oh, the debug module outputs on stderr? Sorry I am just not a user of that module so am not familiar with the way it works. Even so, you don't need to change the fd I think. I tried doing:

$ cat index.js
'use strict'
const debug = require('debug')('foo')
debug('testing')

$ DEBUG=foo node index.js 2> log.txt

$ cat log.txt
2019-06-07T16:09:52.972Z foo testing

Seems to work with the normal stderr fd, right?

[zombieleet]

Yes, that is right. But I see no reason why the default stream should be stderr. But the default stream can be changed to stdout output streams . I think this should be in the docs, most express.js users might be interested in sending the logs to a file rather than the terminal

[wesleytodd]

I see no reason why the default stream should be stderr

I think this is a common best practice for *nix systems, a program's debug output being on stderr. While I understand your viewpoint, I see no reason we should recommend something different from the norm.

I think this should be in the docs, most express.js users might be interested in sending the logs to a file rather than the terminal

This I completely agree with. And I would like to merge this, but I think adding the more complex example might make it harder for beginners to know what is going on. That is why I was hoping to simplify the example to just DEBUG=foo node index.js 2> log.txt.