如何在 Go 中将消息打印到 stderr？

Question

I want to print some logs for debugging and testing, but existing logs are massive, so I want to print my own logs to stderr:

go run main.go 1>/dev/null

So that I can just see my own logs.

How can I do that?

Answer 1

There are multiple methods to send a message to stderr :

1. Creating a new log.Logger :

    l := log.New(os.Stderr, "", 1) l.Println("log message")

2. Using fmt.Fprintf :

    fmt.Fprintf(os.Stderr, "log message: %s", str)

3. Directly writing to os.Stderr using os.Stderr.WriteString :

    os.Stderr.WriteString("log message")

Answer 2

The log package by default prints to os.Stderr .

You can also use os.Stderr directly (it's an os.File ).

Answer 3

On Linux systems, you could also use syslog(3) facilities. By default, the underlying openlog(3) does not go to stderr, but this can be changed.

See Go package log/syslog .