Scenario / Question: I logged into an ssh session on a remote computer and lost my connection, how do I reconnect to the same session ? This trick will help users and system administrators become less frustrated when working on remote systems, and not worry about losing their connection to the [continue...]

Now that we know how to create directories and files we need to be able to rename them and move them. In Linux the command to move and rename is the same ! command to rename and move directories and files NAME mv – move (rename) files SYNOPSIS mv [OPTION]… [-T] SOURCE DEST mv [continue...]

Today we begin learning how to work with the file system. We will cover how to create directories and files. The command to create directories NAME mkdir – make directories SYNOPSIS mkdir [OPTION] DIRECTORY… Lets first change our working directory to the temporary directory /tmp: $ cd [continue...]

Now that we know how to create directories and files, we need to learn how to delete them. There are two commands for deleting or removing directories in linux. The command “rmdir” and “rm”. The “rmdir” and “rm” commands are unforgiving and there is [continue...]

Now that we know how the Linux File system is structured, we need to be able to move around or navigate. Before we can begin navigating we need to be able to list the contents of directories so that we can see where we can go. The command to list a directories contents. NAME ls – list [continue...]

While initially discussion on the file system structure isn’t the most exciting part of Linux. Knowing how the Linux file system is structured will help you understand Linux and be a better Linux user and administrator. The Linux File system is different in that it has One Tree and One [continue...]

Scenario / Question: I can not use yum and appears that iptables is blocking yum from establishing a connection with the internet. Solution / Answer: IPTables needs to be configured to allow incoming ESTABLISHED,RELATED connections and establish connection with yum servers by allowing outgoing [continue...]

Scenario / Question: IPTables is blocking DNS and I can not get DNS from Internet. Solution / Answer: IPTables needs to be configured to allow INPUT of port 53 and the OUTPUT of port 53. DNS uses both tcp and udp protocols on port 53 for communicating. UDP is used for queries transferring less [continue...]

Scenario / Question: How do I find out what service is associated with what port. For example how can I find out what port secure pop3 (pop3s) uses? Solution / Answer: In Redhat based systems there is a file called /etc/services that contains a directory of well known services and their ports. [continue...]

Scenario / Question: How do I install Tomcat on Centos Solution / Answer: In order to install Tomcat on Centos you first need to install Java. Both free and non-free packages are required for the installation. The non-free packages do not cost money however you must download them directly from [continue...]