DNS stands for Domain Name System, or Domain Name Server.
DNS resolves an IP address to a hostname or vice versa.
DNS is basically a large database which resides on various computers that contains the names and IP addresses of various hosts/domains. Other than ip-address DNS also associates various information with the domain names.
In Linux, while typing a command if you press TAB twice, it would list all available commands that starts with typed characters.
This is nothing new, probably you already know about this. This functionality is called bash completion. The basic file and directory name completion are available by default in bash command line.
But, we can turbo-charge this bash completion, and take it to the next level using complete command.
This tutorial explains how we can apply the auto-completion to options and to command’s arguments using programmable completion.
Reverse SSH is a technique that can be used to access systems (that are behind a firewall) from the outside world.
As you already know SSH is a network protocol that supports cryptographic communication between network nodes. Using this protocol, you can do a secure remote login, secure copy from/to a remote machine etc.
Linux has evolved a lot since its inception. It has become the most widely used operating system when in comes to servers and mission critical work. Though its not easy to understand Linux as a whole but there are aspects which are fundamental to Linux and worth understanding.
In this article, we will discuss about Linux processes, threads and light weight processes and understand the difference between them. Towards the end, we will also discuss various states for Linux processes.
In Linux, by default Bash provides the following standard completion for users to use in the command line:
- Variablename completion
- Username completion
- Executable completion
- Filename and directory completion
- Hostname completion
Gdb is an essential tool to debug C programs.
Breakpoints are the way to tell GDB to stop or pause the program execution at certain line, or function, or address. Once the program is stopped you can examine and change the variable values, continue the program execution from that breakpoint, etc.
tmpreaper is a tool to remove files which are not accessed for a certain period of time.
On Linux desktop distros, this is good for cleaning directories like “~/Downloads”, where files get accumulated over a period of time.
On Linux server distros, this is good for cleaning old log files or backup files that are not required any more.
tmpreaper recursively searches and removes files and directories which are not accessed for certain period of time.
If you are running Oracle database on your environment, and having some performance issues because of memory, you may have to look at the swap space configured on your system.
For Oracle 11g database, the following is the recommendation from Oracle in terms of how much space space you should add.