We are not guaranteed that the string we are printing onto stdout contains '\n' and thus that the stdout is flushed. In fact, I've met this problem when virsh asked me whether I want to edit the domain XML again (vshAskReedit()) but the prompt wasn't displayed (as it does not contain a newline character) and virsh just sat there waiting for my input, I sat there waiting for virsh's output. Flush stdout after all fputs()-s which do not flush stdout. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- tools/vsh.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/tools/vsh.c b/tools/vsh.c index bbde594967..499794c8fc 100644 --- a/tools/vsh.c +++ b/tools/vsh.c @@ -1863,6 +1863,7 @@ vshDebug(vshControl *ctl, int level, const char *format, ...) str = g_strdup_vprintf(format, ap); va_end(ap); fputs(str, stdout); + fflush(stdout); } void @@ -1878,6 +1879,7 @@ vshPrintExtra(vshControl *ctl, const char *format, ...) str = g_strdup_vprintf(format, ap); va_end(ap); fputs(str, stdout); + fflush(stdout); } @@ -1891,6 +1893,7 @@ vshPrint(vshControl *ctl G_GNUC_UNUSED, const char *format, ...) str = g_strdup_vprintf(format, ap); va_end(ap); fputs(str, stdout); + fflush(stdout); } @@ -2938,6 +2941,7 @@ vshReadline(vshControl *ctl G_GNUC_UNUSED, int len; fputs(prompt, stdout); + fflush(stdout); r = fgets(line, sizeof(line), stdin); if (r == NULL) return NULL; /* EOF */ -- 2.34.1