x.diff

diff --git a/src/io/syncfile.c b/src/io/syncfile.c
index 82239ca..9b67b94 100644
--- a/src/io/syncfile.c
+++ b/src/io/syncfile.c
@@ -166,6 +166,8 @@ static MVMint64 write_bytes(MVMThreadContext *tc, MVMOSHandle *h, char *buf, M
 /* Flushes the file handle. */
 static void flush(MVMThreadContext *tc, MVMOSHandle *h){
     MVMIOFileData *data = (MVMIOFileData *)h->body.data;
+    if (isatty(data->fd))
+        return;
     if (MVM_platform_fsync(data->fd) == -1)
         MVM_exception_throw_adhoc(tc, "Failed to flush filehandle: %s", strerror(errno));
 }