diff --git a/usage.c b/usage.c
index e4fa6d2f0..82ff13163 100644
--- a/usage.c
+++ b/usage.c
@@ -7,13 +7,21 @@
 #include "cache.h"
 
 static FILE *error_handle;
+static int tweaked_error_buffering;
 
 void vreportf(const char *prefix, const char *err, va_list params)
 {
-	char msg[4096];
 	FILE *fh = error_handle ? error_handle : stderr;
-	vsnprintf(msg, sizeof(msg), err, params);
-	fprintf(fh, "%s%s\n", prefix, msg);
+
+	fflush(fh);
+	if (!tweaked_error_buffering) {
+		setvbuf(fh, NULL, _IOLBF, 0);
+		tweaked_error_buffering = 1;
+	}
+
+	fputs(prefix, fh);
+	vfprintf(fh, err, params);
+	fputc('\n', fh);
 }
 
 static NORETURN void usage_builtin(const char *err, va_list params)
@@ -70,6 +78,7 @@ void set_die_is_recursing_routine(int (*routine)(void))
 void set_error_handle(FILE *fh)
 {
 	error_handle = fh;
+	tweaked_error_buffering = 0;
 }
 
 void NORETURN usagef(const char *err, ...)