8 Windows Command Prompt (CMD) Commands

 

1. Assoc

Most files in Windows are associated with a specific program that is assigned to open the file by default. At times, remembering these associations can become confusing. You can remind yourself by entering the command assoc to display a full list of filename extensions and program associations.You can also extend the command to change file associations. For example, assoc .txt= will change the file association for text files to whatever program you enter after the equal sign. The assoc command itself will reveal both the extension names and program names, which will help you properly use this command.

 

2. Cipher

 

Deleting files on a mechanical hard drive doesn't really delete them at all. Instead, it marks the files as no longer accessible and the space they took up as free. The files remain recoverable until the system overwrites them with new data, which can take some time.

The cipher command, however, lets you wipe a directory on an NTFS-formatted volume by writing random data to it. To wipe your C drive, for example, you'd use the cipher /w:d command, which will wipe free space on the drive. The command does not overwrite undeleted data, so you will not wipe out the files you need by running this command.

When you run the cipher command by itself, it returns the encryption state of the current directory and the files it contains. Use cipher /e:<filename> to encrypt a file, cipher /c:<filename> to retrieve information about encrypted files, and cipher /d:<filename> to decrypt the selected file. Most of these commands are redundant with the Windows encryption tool BitLocker.

3. File Compare

You can use this command to identify differences in text between two files. It's particularly useful for writers and programmers trying to find small changes between two versions of a file. Simply type fc and then the directory path and file name of the two files you want to compare.

You can also extend the command in several ways. Typing /b compares only binary output, /c disregards the case of text in the comparison, and /l only compares ASCII text.

So, for example, you could use the following:

fc /l "C:\Program Files (x86)\example1.doc" "C:\Program Files (x86)\example2.doc"

The above command compares ASCII text in two Word documents.

4. Ipconfig

This command relays the IP address that your computer is currently using. However, if you're behind a router (like most computers today), you'll instead receive the local network address of the router.

Still, ipconfig is useful because of its extensions. ipconfig /release followed by ipconfig /renew can force your Windows PC into asking for a new IP address, which is useful if your computer claims one isn't available. You can also use ipconfig /flushdns to refresh your DNS address. These commands are great if the Windows network troubleshooter chokes, which does happen on occasion.

5. Netstat

Entering the command netstat -an will provide you with a list of currently open ports and related IP addresses. This command will also tell you what state the port is in; listening, established, or closed.

This is a great command for when you're trying to troubleshoot devices connected to your PC or when you fear a Trojan infected your system and you're trying to locate a malicious connection.

6. Ping

Sometimes, you need to know whether or not packets are making it to a specific networked device. That's where ping comes in handy.

Typing ping followed by an IP address or web domain will send a series of test packets to the specified address. If they arrive and are returned, you know the device is capable of communicating with your PC; if it fails, you know that there's something blocking communication between the device and your computer. This can help you decide if the root of the issue is an improper configuration or a failure of network hardware.

7. PathPing

 

This is a more advanced version of ping that's useful if there are multiple routers between your PC and the device you're testing. Like ping, you use this command by typing pathping followed by the IP address, but unlike ping, pathping also relays some information about the route the test packets take.

8. Tracert