An Update on the RunAs Command


This is an update of a post that originally appeared on May 14, 2014.

Recently I wrote the Simulating Users with the RunAs Command post that describes how to use the RunAs command to perform tasks that the user’s account can’t normally perform. (The basics of using the RunAs command appear in Windows Command-Line Administration Instant Reference.) A number of you have written to tell me that there is a problem with using the RunAs command with built-in commands—those that appear as part of CMD.EXE. For example, when you try the following command:

RunAs /User:Administrator "md \Temp"

you are asked for the Administrator password as normal. After you supply the password, you get two error messages:

RUNAS ERROR: Unable to run - md \Temp
2: The system cannot find the file specified.

In fact, you find that built-in commands as a whole won’t work as anticipated. One way to overcome this problem is to place the commands in a batch file and then run the batch file as an administrator. This solution works fine when you plan to execute the command regularly. However, it’s not optimal when you plan to execute the command just once or twice. In this case, you must execute a copy of the command processor and use it to execute the command as shown here:

RunAs /User:Administrator "cmd /c \"md \Temp""

This command looks pretty convoluted, but it’s straightforward if you take it apart a little at a time. At the heart of everything is the md \Temp part of the command. In order to make this a separate command, you must enclose it in double quotes. Remember to escape the double quote that appears within the command string by using a backslash (as in \").

To execute the command processor, you simply type cmd. However, you want the command processor to start, execute the command, and then terminate, so you also add the /c command line switch. The command processor string is also enclosed within double quotes to make it appear as a single command to RunAs.

Make sure you use forward slashes and backslashes as needed. Using the wrong slash will make the command fail.

The RunAs command can now proceed as you normally use it. In this case, the command only includes the username. You can also include the password, when necessary. Let me know if you find this workaround helpful at [email protected].

Author: John

John Mueller is a freelance author and technical editor. He has writing in his blood, having produced 123 books and over 600 articles to date. The topics range from networking to artificial intelligence and from database management to heads-down programming. Some of his current offerings include topics on machine learning, AI, Python programming, Android programming, and C++ programming. His technical editing skills have helped over more than 70 authors refine the content of their manuscripts. John also provides a wealth of other services, such as writing certification exams, performing technical edits, and writing articles to custom specifications. You can reach John on the Internet at [email protected].