Every Admin Should Know These Commands

Active Directory

1. To quickly list all the groups in your domain, with members, run this command:

dsquery group -limit 0 | dsget group -members –expand

2. To find all users whose accounts are set to have a non-expiring password, run this command:

dsquery * domainroot -filter “(&(objectcategory=person)(objectclass=user)(lockoutTime=*))” -limit 0

3. To list all the FSMO role holders in your forest, run this command:

netdom query fsmo

4. To refresh group policy settings, run this command:

gpupdate

5. To check Active Directory replication on a domain controller, run this command:

repadmin /replsummary

6. To force replication from a domain controller without having to go through to Active

Directory Sites and Services, run this command:

repadmin /syncall

7. To see what server authenticated you (or if you logged on with cached credentials) you can run either of these commands:

set l

echo %logonserver%

8. To see what account you are logged on as, run this command:

whoami

9. To see what security groups you belong to, run this command:

whoami /groups

10. To see the domain account policy (password requirements, lockout thresholds, etc) run this command:

net accounts

Windows Networking

11. To quickly reset your NIC back to DHCP with no manual settings, run this command:

netsh int ip reset all

12. To quickly generate a text summary of your system, run this command:

systeminfo | more

13. To see all network connections your client has open, run this command:

net use

14. To see your routing table, run either of these commands:

route print

netstat -r

15. Need to run a trace, but don’t have Netmon or Wireshark, and aren’t allowed to install either one? Run this command:

netsh trace start capture=yes tracefile=c:\capture.etl

netsh trace stop

16. To quickly open a port on the firewall, run this command, changing the name, protocol, and port to suit. This example opens syslog:

netsh firewall set portopening udp 161 syslog enable all

17. To add an entry to your routing table that will be permanent, run the route add command with the –p option. Omitting that, the entry will be lost at next reboot:

route add 0.0.0.0 mask 0.0.0.0 172.16.250.5 –p

18. Here’s a simple way to see all open network connections, refreshing every second:

netstat –ano 1

19. You can add a | findstr value to watch for only a specific connection, like a client ip.addr or port:

netstat –ano | findstr 216.134.217.20

20. You can use the shutdown to shutdown or reboot a machine, including your own, in a simple scheduled task like this:

shutdown –r –t 0 –m \\localhost

21. To make planned DNS changes go faster, reduce the TTL on the DNS records you plan on changing to 30 seconds the day before changes are to be made. You can set the TTL back to normal after you confirm the changes have been successful.

22. Set a short lease on DHCP scopes that service laptops, and set Microsoft Option 002 to release a DHCP leas on shutdown. This helps to ensure your scope is not exhausted and that machines can easily get on another network when the move to a new site.

Windows 7

23. Want to enable the local administrator account on Windows 7? Run this command from an administrative command prompt. It will prompt you to set a password:

net user administrator * /active:yes

24. You can do the same thing during install by pressing SHIFT-F10 at the screen where you set your initial user password.

Windows 7 supports several useful new keyboard shortcuts:

25. Windows Key+G

Display gadgets in front of other windows.

26. Windows Key++ (plus key)

Zoom in, where appropriate.

27. Windows Key+- (minus key)

Zoom out, where appropriate.

28. Windows Key+Up Arrow

Maximize the current window.

29. Windows Key+Down Arrow

Minimize the current window.

30. Windows Key+Left Arrow

Snap to the left hand side of the screen

31. Windows Key+Right Arrow

Snap to the right hand side of the screen.

32. To quickly launch an application as an administrator (without the right-click, run as administrator), type the name in the Search programs and files field, and then press Ctrl-Shift-Enter.

Here are some tips that can save you from buying commercial software:

33. Need to make a quick screencast to show someone how to do something? The Problem Steps Recorder can create an MHTML file that shows what you have done by creating a screen capture each time you take an action. Click the Start button and type ‘psr’ to open the Problem Steps Recorder.

34. Need to burn a disc? The isoburn.exe can burn ISO and IMG files. You can right click a file and select burn, or launch it from the command line.

35. Windows 7 includes a screen scraping tool called the Snipping Tool. I have tons of users request a license for SnagIt, only to find this free tool (it’s under Accessories) does what they need.

36. You can download this bootable security scanner from Microsoft that will run off a USB key, which is very useful if you suspect a machine has a virus.

37. A great way to save all your command line tools and make them available across all your computers is to install Dropbox, create a folder to save all your scripts and tools, and add that folder to your path. That way, they can be called from the command line or any other scripts, and if you update a script, it will carry across to any other machine you have.

Windows 2008

38. You can free up disk space on your servers by disabling hibernate. Windows 2008 will create a hiberfil.sys equal to the amount of RAM. This is very useful with VMs that have lots of RAM but smaller C: drives. To disable hibernation, and reclaim that space, run this command:

powercfg -h off

39. You can get to the complete collection of Sysinternals tools online. You can even invoke them from the run command. Use the url:http://live.sysinternals.com or the UNC path: \\live.sysinternals.com\tools.

40. Speaking of the Sysinternals tools, almost any command line in this article can be run remotely on another machine (as long as you have administrative rights) using the psexec command included in the Sysinternals tools.

41. You can kill RDP sessions at the command line when you find that all the RDP sessions to a server are tied up.

regsvr32 query.dll [enter] You only have to do this the first time.

query session /server:servername [enter]

reset session # /server:servername [enter]

42. You can create a list of files and display the last time they were accessed, which is very useful when a network drive is low on space and users swear they have to have that copy of Office 2003 on the network. My advice? If they haven’t touched it in two years, burn it to DVD or write it to tape and then delete it from disk:

dir /t:a /s /od >> list.txt [enter]

43. The Microsoft Exchange Err command is one of the best all around troubleshooting tools you will find, as it can decode any hex error code you find as long as the products are installed on the machine. Download it from here.

44. You can see all the open files on a system by running this command:

openfiles /query

45. You can pull all the readable data out of a corrupt file using this command:

recover filename.ext

46. Need to pause a batch file for a period of time but don’t have the sleep command from the old resource kit handy? Here’s how to build a ten second delay into a script:

ping -n 10 127.0.0.1 > NUL 2>&1

47. If your Windows website has stopped responding, or is throwing a 500 error, and you are not sure what to do, you can reset IIS without having to reboot the whole server. Run this command:

iisreset

48. You can use && to string multiple commands together; they will run sequentially.

49. If you find yourself restarting services frequently, you can use that && trick to create a batch file called restart.cmd and use it to restart services:

net stop %1 && net start %1

50. You can download a Windows port of the wget tool from here, and use it to mirror websites using this command:

wget -mk http://www.example.com/

Linux

51. You can list files sorted by size using this command:

ls –lSr

52. You can view the amount of free disk space in usable format using this command:

df –h

53. To see how much space /some/dir is consuming:

du -sh /some/dir

54. List all running processes containing the string stuff:

ps aux | grep stuff

55. If you have ever run a command but forgot to sudo, you can use this to rerun the command:

sudo !!

56. If you put a space before a command or response, it will be omitted from the shell history.

57. If you really liked a long command that you just ran, and want to save it as a script, use this trick:

echo “!!” > script.sh