1.ASSOC: Fix File Associations
One of the most powerful tools in the CMD command library is the ASSOC command.
Your computer associates certain file extensions with certain programs. This is how your computer knows to open Adobe when you double click a PDF file, or Microsoft Word when you double click a DOC file.
You can view all the file associations your computer knows about by typing ASSOC in the command window. You’ll see the file extension and the program it’s associated with.
You can set the association by typing something like assoc .doc=Word.Document.8
2. FC: File Compare
Sometimes when files are changed over time, it’s hard to remember what the differences were between versions. You may not know that a CMD command offers the ability to compare files and see all differences, but it’s true.
The FC command performs either an ascii or a binary file comparison and will list all of the differences that it finds.
Fc /a File1.txt File2.txt will compare two ascii files.
Fc /b Picture1.jpg Picture2.jpg will do a binary compare on two images.
3. IPCONFIG: IP Configuration
Network troubleshooting is never simple, but one command that makes it much easier is IPCONFIG.
Using this command in the CMD command prompt returns detailed information about your current network adapter connection including:
- Current IP Address
- Subnet Mask
- Default Gateway IP
- Current domain
This information can help you troubleshoot router issues and other connection issues you could be having with your network adapter.
4. NETSTAT: Network Statistics
Concerned that you could have malware running on your computer that’s connecting to internet locations without you knowing about it?
If you run a NETSTAT command in the command prompt, you can get a list of all active TCP connections from your computer.
5. PING: Send Test Packets
An IT Analyst’s best friend is the PING command. Running this command sends test packets over the network to the target system.
You can use the PING command to test whether your computer can access another computer, a server, or even a website. It can help with revealing network disconnections. It also provides transit time for the packets in milliseconds, so it also reveals a bad network connection as well.
6. TRACERT: Trace Route
TRACERT is a fascinating Windows Command to use. If you’re ever curious to see the path your internet traffic takes to get from your browser to a remote system like Google servers, you can use TRACERT to see it.
The command stands for “Trace Route”, which sends packets out to a remote destination (server or website), and provides you with all of the following information:
- Number of hops (intermediate servers) before getting to the destination
- Time it takes to get to each hop
- The IP and sometimes the name of each hop
TRACERT can reveal how the routes of your internet requests change depending where you’re accessing the web. It also helps with troubleshooting a router or switch on a local network that may be problematic.
7. SYSTEMINFO: System Information
If you need to know what brand of network card you have, processor details, or the exact version of your Windows OS, the SYSTEMINFO command can help.
This command polls your system and pulls the most important information about your system. It lists the information in a clean format that’s easy to read.
8. SFC: System File Checker
If you’re ever concerned that a virus or some other software might have corrupted your core system files, there’s a Windows command that can scan those files and ensure their integrity.
You need to launch CMD as administrator (right-click and choose Run as Administrator). Typing SFC /SCANNOW will check the integrity of all protected system files. If a problem is found, the files will be repaired with backed-up system files.
The SFC command also lets you:
/VERIFYONLY: Check the integrity but don’t repair the files.
/SCANFILE: Scan the integrity of specific files and fix if corrupted.
/VERIFYFILE: Verify the integrity of specific files but don’t repair them.
/OFFBOOTDIR: Use this to do repairs on an offline boot directory.
/OFFWINDIR: Use this to do repairs on an offline Windows directory.
/OFFLOGFILE: Specify a path to save a log file with scan results.
The scan can take up to 10 or 15 minutes, so give it time
9. CHKDSK: Check Disk
While the SFC command only checks the integrity of core system files, you can use the CHKDSK command to scan an entire drive.
The command to check the C: drive and repair any problems, launch the command window as an administrator and type CHKDSK /f C:.
This command checks for things like:
- File fragmentation
- Disk errors
- Bad sectors
The command can fix any disk errors (if possible). When the command is finished, you’ll see a status of the scan and what actions were taken.
10. SCHTASKS: Schedule Tasks
Windows comes with a wizard for creating scheduled tasks. For example, maybe you have a BAT file stored on C:\temp that you want to run every day at noon.
You’d have to click through the Scheduled Task wizard to configure this. Or you can type a single SCHTASKS command to set it up.
SCHTASKS /Create /SC HOURLY /MO 12 /TR Example /TN c:\temp\File1.bat
The scheduled switch accepts arguments like minute, hourly, daily, and monthly. Then you specify the frequency with the /MO command.
If you typed the command correctly, you’ll see the response, SUCCESS: The scheduled task “Example” has successfully been created.
11. ATTRIB: Change File Attributes
In Windows, you can change file attributes by right-clicking on a file and finding the right property to change. However, instead of hunting around for the file attribute, you can use the ATTRIB command to set the file attributes.
For example, if you type: ATTRIB +R +H C:\temp\File1.bat, it’ll set File1.bat as a hidden, read-only file.
There is no response when it’s successful, so unless you see an error message, the command worked.
Other Windows CMD Commands
As you can see, there are some powerful and useful things you can do with the Windows command prompt, if you know the right commands.
Believe it or not, there are even more commands that will give you the ability to do some things you probably never realized just by typing a simple command.
- BITSADMIN: Initiate upload or download jobs over the network or internet and monitor the current state of those file transfers.
- COLOR: Change the background color of the command prompt window.
- COMP: Compare the contents of any two files to see the differences.
- FIND/FINDSTR: Search for strings inside of any ASCII files.
- PROMPT: Change the command prompt from C:\> to something else.
- TITLE: Change the title of the command prompt window.
- REGEDIT: Edit keys in the Windows registry (use with caution).
- ROBOCOPY: A powerful file copy utility built right into Windows.