Get exit code - Go

Question

I'm using the package: os/exec http://golang.org/pkg/os/exec/ to execute a command in the operating system but I don't seem to find the way to get the exit code. I can read the output though

ie.

package main  import(     "os/exec"     "bytes"     "fmt"     "log"     )  func main() {     cmd := exec.Command("somecommand", "parameter")     var out bytes.Buffer     cmd.Stdout = &out     if err := cmd.Run() ; err != nil {         //log.Fatal( cmd.ProcessState.Success() )         log.Fatal( err )     }     fmt.Printf("%q\n", out.String() ) } 

Answer 1

It's easy to determine if the exit code was 0 or something else. In the first case, cmd.Wait() will return nil (unless there is another error while setting up the pipes).

Unfortunately, there is no platform independent way to get the exit code in the error case. That's also the reason why it isn't part of the API. The following snippet will work with Linux, but I haven't tested it on other platforms:

package main  import "os/exec" import "log" import "syscall"  func main() {     cmd := exec.Command("git", "blub")      if err := cmd.Start(); err != nil {         log.Fatalf("cmd.Start: %v", err)     }      if err := cmd.Wait(); err != nil {         if exiterr, ok := err.(*exec.ExitError); ok {             // The program has exited with an exit code != 0              // This works on both Unix and Windows. Although package             // syscall is generally platform dependent, WaitStatus is             // defined for both Unix and Windows and in both cases has             // an ExitStatus() method with the same signature.             if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {                 log.Printf("Exit Status: %d", status.ExitStatus())             }         } else {             log.Fatalf("cmd.Wait: %v", err)         }     } } 

Just follow the api docs to find out more :)

Answer 2

Since golang version 1.12, the exit code is available natively and in a cross-platform manner. See ExitError and ExitCode().

ExitCode returns the exit code of the exited process, or -1 if the process hasn't exited or was terminated by a signal.

if err := cmd.Run() ; err != nil {     if exitError, ok := err.(*exec.ExitError); ok {         return exitError.ExitCode()     } }