Howtos / Articles

adding persistent static routes on centos

When you need to access networks located on a different network segment, you need to have a route set up so the PC knows how to get to the other network segment. This generally just points to your main gateway, but you may want to set up additional static routes, where you don’t want the traffic going through your main default gateway. To set up a static route on CentOS so that it automatically gets created every time the PC…

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Get The Active DNS Servers On Linux

The Domain Name System (DNS for short) is one of the most important parts of the internet infrastructure. It converts the easy to remember domain names, into IP (and IPv6) addresses, that aren’t so friendly to the end user. Regardless of the distribution of Linux that you are using (such as Ubuntu, CentOS, Debian, Arch, Redhat, etc), the process of determining what DNS servers are currently being used for domain name resolution is the same. To determine what DNS servers…

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Using sed to replace a string in a file

The ‘sed’ command can be used to easily replace all occurrences of one string in a text file, with another string. For example: sed -i “s/wordtofind/replacewithword/g” /path/to/file.txt This command will find all occurrences of “wordtofind” and replace them on the fly with “replacewithword” in the file “/path/to/file.txt”. The “-i” command switch specifies to edit the file in place, otherwise it will just display the output to the standard output. Run it without the “-i” switch to ensure it runs correctly,…

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Install the dig DNS lookup utility on CentOS

The dig DNS lookup utility is a handy tool for performing DNS queries. The dig utility is part of the bind utilities package in CentOS. The following command can be used to install dig. Install dig (the bind-utils package): # yum install bind-utils Note: Make sure you run the above command as a user with root privledges. You should now be able to use dig to perform DNS lookups. See ‘man dig’ for more information.…

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List all hard disks connected to a CentOS system

You often need to know what physical drives are attached to a system, how many drives are connected, or even what device names match up with which physical drive. There is a handy tool called ‘lshw’ which is used to extract detailed information on the hardware in the PC. Unfortunately this doesn’t come pre-installed on CentOS. The details below will go through installing lshw, and how to run it to list all the hard drives. Prerequisites This guide requires the…

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