Move FatalOnErr to exitcode.go

exitcode.go

@@ -6,6 +6,7 @@ package errors
 
 import (
 	"fmt"
+	"os"
 )
 
 // ExitCoder interfaces provide access to an exit code.
@@ -58,6 +59,15 @@ func GetExitCodeOr(err error, or int) int {
 	return or
 }
 
+// FatalOnErr prints the error to stderr and exits the program with an exit
+// code that is not 0. When err is an ExitCoder its exit code is used.
+func FatalOnErr(err error) {
+	if err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "\nFatal error: %+v\n", err)
+		os.Exit(GetExitCodeOr(err, 1))
+	}
+}
+
 type exitCodeError struct {
 	*embedError
 	exitCode int