The Geek Stuff » FAQ

HBA WWN: How to Find Qlogic or Emulex HBA Card WWN Address on Linux

Ramesh Natarajan — Fri, 20 Aug 2010 06:02:57 +0000

Question: How do I lookup the wwn address of my HBA card installed on the Linux system. I need this information to create zoning on my fiber channel switch. Answer: Use one of the following methods to view the HBA WWN address on Linux. Method 1: /sys/class/scsi_host/host{n}/device/fc_host:host{n}/port_name File On Redhat 5 and above (including OEL [...]

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How to Allow MySQL Client to Connect to Remote MySQL server

Ramesh Natarajan — Thu, 12 Aug 2010 06:02:50 +0000

By default, MySQL does not allow remote clients to connect to the MySQL database. If you try to connect to a remote MySQL database from your client system, you will get “ERROR 1130: Host is not allowed to connect to this MySQL server” message as shown below. $ mysql -h 192.168.1.8 -u root -p Enter [...]

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How to Register RHEL/OEL Linux to Oracle Support (ULN) using up2date

Ramesh Natarajan — Fri, 06 Aug 2010 06:02:56 +0000

Question: I have purchased Linux support for RHEL and OEL from Oracle corporation. How do I register my Linux system to Oracle support network to download and update packages? Can you explain me with step-by-step instruction? Answer: After purchasing Linux support from Oracle, you should register your Linux system with Oracle’s Unbreakable Linux Network using [...]

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Unix Shell Script to Execute Oracle SQL Query

Sasikala — Fri, 30 Jul 2010 06:02:52 +0000

Question: Can you provide me a shell script that will accept oracle credentials, sql query to be executed and displays the output? Answer: The shell script given below prompts some basic information and displays the output of the SQL. You can use the same concept and hard-code some of these values in the shell-script itself [...]

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How to Fix wget Connection Refused Error when I’m behind a Proxy

SathiyaMoorthy — Fri, 23 Jul 2010 06:02:17 +0000

Question: While downloading using wget, I get the following error “Connecting to <URL>.. failed: Connection refused.”. I’m behind a proxy server. How do I fix it? Answer: Export the http_proxy variable with your proxy server name or ip address and then try downloading as explained below. Connection refused error while using wget If http_proxy environment [...]

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[FIXED] OpenSSH Slow: Hanging at SSH2_MSG_SERVICE_ACCEPT received

Ramesh Natarajan — Fri, 16 Jul 2010 06:04:04 +0000

Question: When I’m trying to ssh to a remote server, after I enter the username, it takes a lot of time before it displays the password prompt. Basically, my SSH ( openSSH ) is slow during authentication process. How do I solve this problem? Answer: If your ssh login from localhost to remotehost is slow, [...]

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How to View and Delete Iptables Rules – List and Flush

SathiyaMoorthy — Fri, 16 Jul 2010 06:02:24 +0000

Question: How do I view all the current iptables rules? Once I view it, is there a way to delete all the current rules and start from scratch? Answer: Use the iptables list option to view, and iptables flush option to delete all the rules as shown below. You should have root permission to perform [...]

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How To Disable Ping Replies in Linux using icmp_echo_ignore_all

SathiyaMoorthy — Fri, 09 Jul 2010 06:02:21 +0000

You may want to disable ping replies for many reasons, may be for a security reason, or to avoid network congestion. Someone can flood the network with ping -f as shown in “Ping Example 5″ in our earlier Ping Tutorial article. If ping reply is disabled we can avoid this flooding. Disable ping reply Temporarily [...]

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xhost+ : How to Fix “Cannot Open Display” Error While Launching GUI on Remote Server

SathiyaMoorthy — Fri, 25 Jun 2010 06:04:07 +0000

Question: When I try to launch any GUI application on a remote server, I’m getting the “cannot open display:” error, as shown below. How do I fix this? For example, while launching the gedit on remote server, I got the following message. (gedit:3658): Gtk-WARNING **: cannot open display: I get similar message when I try [...]

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Forth Hello World Example: How To Write and Execute Forth Program on Linux OS

SathiyaMoorthy — Fri, 25 Jun 2010 06:03:31 +0000

Question: I would like to understand the basics of how to write and execute Forth program on Linux OS. Can you explain it with a simple example? Answer: If you’ve never heard about Forth program, read about it in Wikipedia first. In this article, let us review very quickly how to write a basic Hello [...]

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