How can I redirect the stdout and stderr of a command to both the console and a log file while outputting in real time?

Question

The following bit of code does exactly what I want, except it only prints to the console.

cmd := exec.Command(\"php\", \"randomcommand.php\")

cmd.Stdout =          


        

Answer 1

As I said in the comment section, this can be achieved using MultiWriter

package main

import (
    "io"
    "log"
    "os"
    "os/exec"
)

func main() {
    // Logging capability
    f, err := os.OpenFile("log.log", os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
    if err != nil {
        log.Fatalf("Error opening file: %v", err)
    }
    defer f.Close()
    mwriter := io.MultiWriter(f, os.Stdout)
    cmd := exec.Command("ls")
    cmd.Stderr = mwriter
    cmd.Stdout = mwriter
    err = cmd.Run() //blocks until sub process is complete
    if err != nil {
        panic(err)
    }
}

When you declare your command, and before you run it, just specify that Stdout and Stderr are using the MultiWriter defined above. This MultiWriter instance contains both a log file and the standard output.