Free Dynamic DNS with Custom Domain

If you need to administer your home network remotely from office, you will either need to know the public IP address assigned by your ISP or use a service called dynamic DNS, that will map a DNS hostname to your IP address. Dynamic DNS is required as the public IP address assigned by your ISP is never fixed for consumer broadband connections.

How to Intrepret Shadow Passwords in UNIX

In modern UNIX and Linux systems, user passwords are encrypted and stored in the /etc/shadow file. On BSD systems, the passwords are kept in the /etc/master.passwd file. The encrypted password field in the file contains more than just the encrypted password, it contains additional information.

How to Determine the Linux Distribution

Linux is a very customisable UNIX like operating system. To date, there are more than a couple of dozen Linux distributions available, based on this Wikipedia list.

Shell Script: Calculate Yesterday’s Date on UNIX

shell script

There are times when you will need to calculate yesterday’s date in a UNIX shell script to run some date sensitive cron jobs. There are currently no standard command line tools in UNIX to perform such date arithmetic.

Manipulate Windows Registry from the Command Line

The Registry Editor, or regedit.exe, allows the import and export of Windows registry entry files from the command line. It’s usage though, could prove to be a bit restrictive from the command line. From Windows XP edition onwards, Microsoft has included another command line tool called REG, or reg.exe. This tool is able perform almost all the tasks as it’s GUI counterpart – regedit.exe.

Recursive FTP from the Command Line

The default command line ftp client in most UNIX distributions do not support recursive downloads, even though recursive downloads is a basic feature in most GUI based ftp clients. But if you do not have access to the X-Windows or GUI, there are alternative ways to achieve the same result from the command line.

UNIX Terminal Session Management

Have you ever encountered the dreaded “Connection closed by foreign host” message when you were logged into a remote server via SSH and you were in the middle of some important task? You have most probably just lost your session and you will have to start your task all over again. Well, you can prevent this from happening by using the screen command available in most UNIX and Linux distributions.

How to Disable a CPU Core

Multi-core CPUs pack multiple processors into a single chip thus allowing multiple threads to run at once. Most of the time, this is a good thing. But at times, for example, when you need to run some legacy applications that are not compatible with multi-core processing, you may be required to disable the cores.