Error: Could not open command file ‘/usr/local/nagios/var/rw/nagios.cmd’ for update!

If you’re updating nagios, and/or you are trying to reschedule checks manually, and you get the error below: Error: Could not open command file ‘/usr/local/nagios/var/rw/nagios.cmd’ for update! Then it means that the permissions on the folder are messed up. Don’t bother setting up the permissions on the file itself, nagios.cmd,  since that file gets recreated very often, so: chown nagios.nagcmd …

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How to install cron (crond, crontab)

Are you looking for crontab on a new install of CentOS 5? Well if you do a custom installation and don’t select anything then it will not be installed by default. In order to install it there just needs to be one package installed. See the below commands to install and setup crontab. Use this command to install crontab, start …

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How To Create A RAID-1 Setup On A CentOS/RedHat 6.0 Server

  This tutorial is for turning a single disk CentOS 6 system into a two disk RAID1 system. The GRUB bootloader will be configured in such a way that the system will still be able to boot if one of the hard drives fails (no matter which one).   NOTE: Everything has to be done as root: su - enter …

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Linux Centos 6 Change Server Hostname

I am a new CentOS Linux server user. How do I change hostname on CentOS Linux? How can I change server hostname on CentOS Linux  6? You need to use the following commands to set or view current hostname, domain name and/or FQDN (Fully Qualified Domain Name): dnsdomainname command : Display the system’s DNS domain name. hostname command : Show or …

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Installing Plex Media Server on Centos 6

Plex Media Server is a user-friendly way to store all your movies, shows, and other media in one place–and make it accessible from any device, whether you’re at home or on-the-go. If you’re looking for a no-headache way to watch your movies anywhere, this is it. What Is Plex Media Server? Here’s a common situation that all too many people find themselves …

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ConfigServer Firewall : Binary location for [/usr/bin/host] in csf.conf is either incorrect, is not installed or is not executable

The following error may occur while reloading CSF (csf -r) : *WARNING* Binary location for [HOST] [/usr/bin/host] in /etc/csf/csf.conf is either incorrect, is not installed or is not executable *WARNING* Missing or incorrect binary locations will break csf and lfd functionality In this particular case, CSF was installed on a CentOS 7 server and there wasn’t any “host” executable under /usr/bin. …

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Linux / UNIX: Create Large 1GB Binary Image File With dd Command

How do I create 1 GB or 10 GB image file instantly with dd command under UNIX / Linux / BSD operating systems using a shell prompt? You can use dd command to create image files for network or file system testing. First, make sure you’ve sufficient disk space to create a image file using dd:   $ df -H …

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