T-SQL has some amazing features. Besides being able to do all the standard SQL stuff with ease and poise, it can also do some heavy lifting by reaching out into the OS with some mighty Stored Procedures. A short while back I had the pleasure to acquaint myself with the xp_cmdshell stored procedure.
In a nutshell the xp_cmdshell provides an interface with the OS Command Shell and allows the user the same possibilities as opening and running commands from a shell window or a batch file. Imagine being able to query different parts of the file structure or a remote computer’s configuration and storing this information in a table for reporting purposes. Of course in order to perform these operations, you need administrative access. You also need to enable the stored procedure and for a production environments your security needs to be tightly controlled so not to allow access to any undesirables.
Configure xp_cmdshell on SQL Server
Using the xp_cmdshell Stored Procedure requires enabling it on the SQL Server. You can accomplish this by sp_Configure Stored Procedure followed by the Reconfigure statement to install the new configuration. The general syntax is :
sp_Configure OptionName, ConfigValue
To enable the xpCmdShell Stored Procedure, open a query page in SSMS or another SQL editor, add the following code and execute
Get File System output
Once SQL Server is reconfigured for xp_cmdshell you can write commands like you would do from any command shell. As an example suppose you would want to view a list of exe files that is on a computer or server on the network for reporting purposes. This could be accomplished with the following command:
Volume in drive C has no label.
Volume Serial Number is 9CBD-D644
Directory of C:\WINDOWS\system32
01/24/2007 03:28 PM 124,928 accelerometerST.exe
04/14/2008 06:42 AM 184,320 accwiz.exe
04/14/2008 06:42 AM 4,096 actmovie.exe
04/14/2008 06:42 AM 98,304 ahui.exe
04/14/2008 06:42 AM 44,544 alg.exe
04/14/2008 06:42 AM 142,848 bootcfg.exe
08/04/2004 08:00 AM 15,872 expand.exe
04/14/2008 06:42 AM 24,064 extrac32.exe
08/04/2004 08:00 AM 882 fastopen.exe
04/14/2008 06:42 AM 20,992 faxpatch.exe
08/04/2004 08:00 AM 14,848 fc.exe
08/04/2004 08:00 AM 9,216 find.exe
04/14/2008 06:42 AM 27,136 findstr.exe
08/04/2004 08:00 AM 9,216 finger.exe
08/04/2004 08:00 AM 3,072 fixmapi.exe
04/14/2008 06:42 AM 23,040 fltmc.exe
04/14/2008 06:42 AM 20,992 fontview.exe
04/14/2008 06:42 AM 7,680 forcedos.exe
04/14/2008 06:42 AM 14,848 stimon.exe
04/14/2008 06:42 AM 165,888 wuauclt1.exe
09/28/2006 06:56 PM 146,432 WudfHost.exe
08/04/2004 08:00 AM 32,256 wupdmgr.exe
04/14/2008 06:42 AM 30,720 xcopy.exe
372 File(s) 72,569,014 bytes
0 Dir(s) 22,951,780,352 bytes free
Store Command Shell Output in Temporary Table
If you wanted to store that information in a temp table, you could execute the following command:
Store Command Shell Output in Table Variable
Alternatively, you could store that information in a table variable by executing this command instead:
If you need to capture the return code, you would first declare a variable for the codfe and append the variable assignment in front of the command like this:
The print @ret would return 0 for success. A failure would have returned a 1. Notice also the No_Output option. This tells the cmd to not direct any output to the screen.
You may like to read this tutorial on using PowerShell from T-SQL in SQL Server as well
This is only a brief introduction into the endless possibilities at your fingertips and as I said at the beginning you can execute any command that is available from the Command “Cmd” shell and you can combine this output with other output from other commands and store this information neatly in a table.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
AmjiBhai on October 11, 2019:
Thank you for nice information...Just need to know that am accessing SqlServer remotely...and if I run the following shell command
exec xp_cmdshell 'dir *.exe'
will it enlist the exe files located on the server or the files located on my machine.?
shay chanuni on August 10, 2017:
thank you so much , was very helpfull.
Paul on January 27, 2017:
You think after 20 years, MS SQL would have a better way, outside of using CLRs, to interact with the o/s. I understand there are some xps, but still very clumsy, and loss of control, a bad xp_cmdshell command not caught in try/catch block/. Wen always have OLE Automation, which I actually prefer over xp_cmshell.