Tag: Net

Obtaining Command Line Help

Both Administering Windows Server 2008 Server Core and it’s more diminutive counterpart, Windows Command-Line Administration Instant Reference, are reference manuals that tell how to use the command line to perform specific tasks. The first book is more complete, in that it contains many uncommon commands and utilities. The second book is designed to provide more hands-on help by supplying a significant number of actual usage examples. In both cases, you get a significant amount of help about the commands. As long as you have one of these two books by your side, you’re in great shape for knowing how to use the commands at the command line. Unfortunately, the reality is that most of us don’t stuff a library full of books in our back pocket. Even with an e-Reader, such as the Kindle, you can be sure of having the device available every time you need it. So, how do you get at least some quick help when there aren’t any resources available?

The first thing to remember is that you can get at least some useful information for any command or utility by using the /? or -? command line switches (some commands and utilities are peculiar in that they require either the /? or the -? command line switch, while many will allow you to use either). For example, when you want to discover how to use the Dir command, you type Dir /? and press Enter. Here’s typical output when using the /? command line switch.

GettingHelp01

This help screen is also typical in showing what you get. Help normally includes a short description of the command, the command line syntax, and a short description of each of the command line switches. You may also see usage examples for more complex commands. In rare cases, the help screen will provide an URL for additional help.

Some commands and utilities are complex enough that they require several help screens. For example, if you type WMIC /? and press Enter, you’ll see a list of help topics, not help of the sort provided for the Dir command. Let’s say you want to know more about the CPU topic. So, now you type WMIC CPU /? and press Enter. The help looks a little more normal now, but still isn’t very complete because you need to choose a subcommand. Perhaps you want just a list of CPUs on a system, so you request information about the List subcommand by typing WMIC CPU List /? and pressing Enter. Wow, now you see a number of listing formats. This time you add a listing format by typing WMIC CPU List Brief /? and pressing Enter. It turns out that you can also discover information about command line switches used with the Brief format. The final level in this case is to type WMIC CPU List Brief /Translate /? and press Enter. The WMIC utility is unique in providing so many levels of help, but other complex commands and utilities, such as Net, do provide multilevel help.

No matter how many help screens you see, sometimes it isn’t enough to give you the help you need. That’s when you need to find your copy of my book to get additional information. Of course, a single book can do only so much—some complex commands and utilities may require still more information. Technet is a good place to start. For example, you can find an excellent article on WMIC at http://technet.microsoft.com/library/bb742610.aspx. Knowledge base articles also provide useful information, especially when it comes to issues that Microsoft has solved for a given command or utility. For example, the Knowledge Base contains an article entitled, “How to find computer serial number” that relies on WMIC. Finally, make sure you look at third party articles, such as the one entitled, “WMIC: the best command line tool you’ve never used.”

Many people complain about not being able to remember all of the commands and utilities, and this is a problem. After you use a command or utility often enough, you tend to remember it, but the memorization process can take time. Unfortunately, there isn’t any single quick method of finding every command or utility on a system. However, you should start by typing Help | More and pressing Enter. (Using the More command lets you see the information that a utility has to provide one screen at a time, rather than seeing the information scroll right past.) You’ll get a list of common commands like this one.

GettingHelp02

Not all of the commands appear on this list and none of the utilities do. Another way to obtain the information you need is to type Dir *.COM and press Enter in the \Windows\system32 directory. (You can type CD \Windows\System32 and press Enter to get to the appropriate directory.) Every directory entry you see is very likely a utility. However, many utilities are in .EXE form, so you also need to type Dir *.EXE | More and press Enter. You can eliminate files that contain more than eight letters in the filename from the list in most cases because command line utilities usually rely on the old 8.3 naming convention. Check filenames that look like they could be what you want by typing Filename /? and pressing Enter (where Filename is the name of the file you want to test). Useful command line utilities will generally display a help screen.

Now that you have a better idea of how to get command line help when you need it and where to obtain a list of useful commands and utilities, you should take some time to try it out for yourself. What techniques do you use to obtain the additional information you need at the command line? Let me know at [email protected].

 

Working with Net User

The Net User command on page 142 of Windows Command-Line Administration Instant Reference seems to have generated a bit of confusion. The /Add command line switch is straightforward; /LogonPasswordChg isn’t. For one thing, the /LogonPasswordChg command line switch doesn’t appear to be documented, even in Windows 7. Here’s the help provided with Net User now:

NetUser01

As you can see, not even a mention for /LogonPasswordChg. Microsoft doesn’t help matters. For example, if you look at the “How to Use the Net User Command” Knowledge Base article, you won’t find any mention of this command line switch. While writing the book, I had found a tantalizing clue at Manage XP and Vista Users Using DOS Commands and decided to try it on Windows 7 as well. The command works fine when used correctly in Windows 7.

However, here is where the plot thickens. It seems that the command line switch doesn’t work in Windows XP. When you execute the command shown on page 142 you get an error message reading something like, “The option /LOGONPASSWORDCHG:YES is unknown.” Somewhere between Windows XP and Vista, Microsoft added the /LogPasswordChg command line switch to Net User and then didn’t tell anyone about it. Consequently, the command shown on page 142 won’t work under Windows XP.

There is another problem that occurs when using the /LogonPasswordChg command line switch. If the account currently has the Password Never Expires option checked as shown here:

NetUser03

the command appears to succeed, but doesn’t change anything. In order to make the command work properly, you must first set the password to expire using the WMIC Path Win32_UserAccount Where Name=’UserName’ Set PasswordExpires=True command. So, the sequence to set an existing account to force a password change during the next logon is like this:

NetUser04

When you execute these two commands, you’ll see the user account settings to change to appear like this:

NetUser05

which means the user must change the password during the next logon.

So, why does the command on page 142 work without this extra step? In this case you’re adding a new user and the Password Never Expires option is disabled by default. Creating the combined command works fine because there is nothing to hinder it with a new account. Please let me know if you encounter any problems with this particular command at [email protected].

 

Deleting a Session at the Command Line

A reader of my book, Windows Command-Line Administration Instant Reference, recently wrote in to say that the Net Sessions /Delete command apparently doesn’t work, which I found interesting because I’ve tested it on a number of occasions and found it always worked for me. It turns out that we had two different scenarios in mind. Normally, you’ll use the Net Sessions /Delete command to free up resources when a remote terminal has frozen or left the session intact in some other way. For whatever reason, the remote user didn’t log out and that means all of the file locks are still in place, for one thing, and that all of the session resources are in use, for another. Using Net Sessions /Delete cleans up this mess, but only at the potential expense of data loss and all of the other things that go with terminating a session without following the usual protocol.

In this case, the reader was simply trying the command to see if it would work. However, the command didn’t appear to work become the remote terminal was still active. Since Windows XP SP1 there has been an automatic reconnection feature.  You disconnect the session and Windows XP (and above) automatically reconnects it. You can read about it at http://support.microsoft.com/kb/323258.

Microsoft used to say that you had to turn this feature on manually (such as by using a policy). The fact of the matter is that the sessions automatically reconnect by default. You’ve probably seen it work already. For some reason, the network disconnects. However, after a few seconds, you magically see the network connection reappear. I know I’ve even seen it on my network. There isn’t anything magic about it—the session is being automatically reconnected in the background without any interaction from you. So…while the command does in fact work, it’s disabled by the automatic reconnection feature. Windows can reconnect faster than you can disconnect it.

Of course, this makes me wonder about other commands that apparently don’t work, but are merely thwarted by well-intentioned Windows behavior. Let me know if you see any behavior of this sort at [email protected].