From 705beb4c25f976f6bce40818bd835e235c2babf4 Mon Sep 17 00:00:00 2001 From: Felix Lange Date: Wed, 27 May 2015 15:48:07 +0200 Subject: [PATCH] cmd/utils: print errors only once if stdout and stderr are the same file --- cmd/utils/cmd.go | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/cmd/utils/cmd.go b/cmd/utils/cmd.go index 550ac1c51..06c240bd4 100644 --- a/cmd/utils/cmd.go +++ b/cmd/utils/cmd.go @@ -125,10 +125,17 @@ func initDataDir(Datadir string) { } } -// Fatalf formats a message to standard output and exits the program. +// Fatalf formats a message to standard error and exits the program. +// The message is also printed to standard output if standard error +// is redirected to a different file. func Fatalf(format string, args ...interface{}) { - fmt.Fprintf(os.Stderr, "Fatal: "+format+"\n", args...) - fmt.Fprintf(os.Stdout, "Fatal: "+format+"\n", args...) + w := io.MultiWriter(os.Stdout, os.Stderr) + outf, _ := os.Stdout.Stat() + errf, _ := os.Stderr.Stat() + if outf != nil && errf != nil && os.SameFile(outf, errf) { + w = os.Stderr + } + fmt.Fprintf(w, "Fatal: "+format+"\n", args...) logger.Flush() os.Exit(1) }