If ":" is omitted, use same name for package and script in pub global run.

sdk/lib/_internal/pub/lib/src/command/global_run.dart

Index: sdk/lib/_internal/pub/lib/src/command/global_run.dart
diff --git a/sdk/lib/_internal/pub/lib/src/command/global_run.dart b/sdk/lib/_internal/pub/lib/src/command/global_run.dart
index 707fdea4c1592f5dbe612908a9c4868d19361f7d..7c065c887dafae9393eff39598b6046555f1957f 100644
--- a/sdk/lib/_internal/pub/lib/src/command/global_run.dart
+++ b/sdk/lib/_internal/pub/lib/src/command/global_run.dart
@@ -26,20 +26,25 @@ class GlobalRunCommand extends PubCommand {
   bool get allowTrailingOptions => false;
   String get description =>
       "Run an executable from a globally activated package.";
-  String get usage => "pub global run <package> <executable> [args...]";
+  String get usage => "pub global run <package>:<executable> [args...]";
 
   Future onRun() {
     if (commandOptions.rest.isEmpty) {
-      usageError("Must specify a package and executable to run.");
+      usageError("Must specify an executable to run.");
     }
 
-    if (commandOptions.rest.length == 1) {
-      usageError("Must specify an executable to run.");
+    var package;
+    var executable = commandOptions.rest[0];
+    if (executable.contains(":")) {
+      var parts = split1(executable, ":");
+      package = parts[0];
+      executable = parts[1];
+    } else {
+      // If the package name is omitted, use the same name for both.
+      package = executable;
     }
 
-    var package = commandOptions.rest[0];
-    var executable = commandOptions.rest[1];
-    var args = commandOptions.rest.skip(2);
+    var args = commandOptions.rest.skip(1).toList();
 
     return globals.find(package).then((entrypoint) {
       return runExecutable(this, entrypoint, package, executable, args);