improve CLI usability (#4670)

closes #3308

1 files changed, 6 insertions, 1 deletions

diff --git a/bin/uglifyjs b/bin/uglifyjs
index 60335426..35f06412 100755
--- a/bin/uglifyjs
+++ b/bin/uglifyjs
@@ -260,9 +260,14 @@ if (paths.length) {
     });
     run();
 } else {
+    var timerId = process.stdin.isTTY && process.argv.length < 3 && setTimeout(function() {
+        print_error("Waiting for input... (use `--help` to print usage information)");
+    }, 1500);
     var chunks = [];
     process.stdin.setEncoding("utf8");
-    process.stdin.on("data", function(chunk) {
+    process.stdin.once("data", function() {
+        clearTimeout(timerId);
+    }).on("data", function(chunk) {
         chunks.push(chunk);
     }).on("end", function() {
         files = { STDIN: chunks.join("") };