Sometimes you want to find the size of all files that match some criteria, for example: files older than N days, or files greater than N bytes, or files that have a certain extension.
In this case, using du is not practical. Here is a simple awk one-liner that will sum the size of all files [...]

Why
If you travel a lot like me, you may find yourself in need to change the mac address of your gizmos to avoid paying multiple times for the same service.
Many hotspot services (commonly found in hotels) require you to pay for an access code for each wireless device that you bring with you. Usually these [...]

How do I Flush DNS?
How to Flush DNS in Microsoft Windows
In Microsoft Windows, you can use the command ipconfig /flushdns to flush the DNS resolver cache:
C:\>ipconfig /flushdns

Windows IP Configuration

Successfully flushed the DNS Resolver Cache.
You can also use the command ipconfig /displaydns to view the DNS resolver cache
How to Flush DNS in Mac OSX
In Mac OSX [...]