/ - rtt - IT Resource

  • systemd management using systemctl and journalctl to check systemd logs


    systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system. The key commands or arguments you will use with systemctl are the following: Unit Commands:   list-units [PATTERN...]         List loaded units &nbs........
  • Linux Mint Ubuntu Debian How To Disable Webcam Automatically Onboot To Prevent Spying and Privacy Violations


    It is well known hackers, the NSA, CIA and other groups have created malware to secretly turn on your webcam and microphone on your phone, tv etc.. But fortunately on our computers and laptops we have some options. Most webcams use the "uvcvideo" kernel module / driver.  You can disable this in two ways on boot. I recommend both just as a failsafe.  Disable it on rc.local once your system boots automatically Add the followi........
  • Migrate Centos 7 from Single HDD to mdadm RAID 10 array:


    Done on Centos 7.3 very important as clearly based on older guides it was a lot easier and more simpler!  Hint do not use grub2-install! One huge caveat if you are an oldschool user or sysadmin who has avoided UEFI booting The normal way will not work here if your Centos was using UEFI.  Newer systems use it by default. The easiest way to check is to do an fdisk -l if your sy........
  • Intel NUC J3455 Linux Support Ubuntu/Linux Mint Issues


    I get the following error "Installer Crashed" on 18.1 MATE 64-bit when installing by NFS/PXE.  Yet it was able to at least detect and use my NIC (perhaps the driver was only activated because of PXE/NFS being used)? When using 18.1 Cinnamon on CD the NIC does not work but the installer did succeed.  However it doesn't work right, I can't login graphically and get some Cinnamon OOM error but how can this be with 8GB of RAM straight from login?........
  • Cannot Read License File cPanel Solution


    This can happen because port 80 is not open, or your license has expired and/or your IP is out of date and also if the license server itself from cPanel is having issues. In most cases as long as you have a valid license the following command will solve it:  /usr/local/cpanel/cpkeyclt Updating cPanel license...Done. Update succeeded. Building global cache for cpanel...Done   Cannot........
  • Wordpress Plugin manual install how-to


    This is the most secure way since we don't know if using the built-in ftp method of Wordpress is secure (that is do they store, record or transmit the ftp login information to a third party like the NSA?). Upload or wget the plugin and then unzip it from the Wordpress website tot he following path of your wordpress: /yourwordpressinstall/wp-content/plugins Then navigate to the "Plugins" section on the left side o........
  • Windows 2008 Server Trial How To Activate & Extend the Trial


    To activate your Windows 2008 server trial which gives you 180 days: Start -> Right Click (My Computer). Click "Activate Windows now" To renew your license for 6 days (can be done 3 times): Start -> Type this command: slmgr.vbs -rearm Wait a few minutes until it says it is successful (unless you get that message it has not worked or been done)........
  • Wordpress Security Hole, Plug it by manually installing themes and plugins


    It's always bothered me how Wordpress basically forces the user to provide their hosting credentials to install themes and plugins.  How do know for sure the data is not being saved, intercepted and being provided backdoor access to the NSA or other agencies or even just being misused by others with access? Here's how to close the security hole above and if you're already given Wordpress your credentials make sure you change everything associated it with it.  Eg. change your........
  • LVM How-To Activate and Access Volumes/Data


    vgchange -ay   3 logical volume(s) in volume group "vg_12" now active lvscan   inactive          '/dev/vg_12/lv_root' [144.04 GB] inherit   inactive          '/dev/vg_12/lv_home' [1.00 GB] inherit   inactive          '/dev/vg_12/lv_swap' [7.85 GB] inherit........
  • kvm cannot boot xen guest using lvm


    This booting error is because the Xen PV guest image uses the Xen kernel, this is not compatible with anything but a host running a Xen kernel. I did a kpartx -av virtual.img and then it created some partitions that showed up in fdisk. I mounted it and did a chroot into it and removed the xen kernel and installed a normal kernel but Xen still shows the same kernel in Grub (only the Xen one). This is strange but it seems like this Xen PV guest has some sort of hidden or........
  • Ubuntu 10 Nvidia Drivers Not Updated After Kernel Update Solution/How-To Manually Rebuild nvidia kernel modules for Ubuntu


    I dread updating the kernel and rebooting to find the Ubuntu graphics aren't working and you have to manually intervene.   This is usually because Ubuntu for whatever reason didn't update the drivers you need (eg. the manually compiled Nvidia Kernel driver that MUST be recompiled for each and every kernel update unfortunately). The most common reason may be that "linux-source" hasn't been installed automatically on my system.  I tried to manually reinstall the........
  • Linux Out of Memory OOM Object Killer Solution "Out of memory: kill process 1955 (sshd) score 81 or a child"


    I had a system running a 128MB live CD image with 2.8 gigs of available RAM and the OOM kernel killer went crazy when using dd for more than 8 minutes and kept killing everything.  I've read that this is due to a low-memory issue and paging in the kernel and 32-bit systems with lots of RAM. I even enabled swapspace on my LiveCD and the issue happened 25 minutes into dd rather than 8 minutes, so what gives? Also no swap space was ever used! cat /proc/s........
  • 2011 Best Laptop - HP 15.6" Laptop featuring AMD Athlon II P340 Processor (G62-420CA)


    My mother needed a new laptop and I recommended her the same one I would have bought myself or my wife, that means the cheapest possible laptop with the most features for the money. This HP shines at this price point and one thing that made me stay away from buying more and recommending HP/Compaq was the poor battery life.  Not anymore, this model has an industry leading up to 4 hours of battery life. Key Factors for Choosing It: HDMI Out........
  • CPU #1 not responding - cannot use it.


    I think this will be useful to others because I have a server that kept crashing mysteriously during intense disk usage/RAID checks.  It would only crash during the weekly RAID integrity check. Then I noticed during a reboot that not all CPUs were being brought up, as a result this actually creates much higher temperatures with the output I got from sensors, just booting the system produced higher than normal temperatures. You can imagine that a full blown RAID check........
  • How To Set DHCP/Static IP Address in Centos/RHEL/Fedora & Debian/Ubuntu/Kubuntu/MEPIS Set DHCP/Static IP Address


    Basically the two main types of distros are Debian and RHEL/Centos based.  I'm just going to give a quick overview of how the configuration of IP interfaces works in Debian/Centos based distros. *Just one thing to remember, when setting IPs statically you have to manually specify a DNS server in /etc/resolv.conf (since DHCP is what normally does it automatically) Debian/Ubuntu/Kubuntu/MEPIS The IP (DHCP &........
  • Vonage & Linksys Offer Trade-In Program


    Vonage & Linksys Offer Trade-In ProgramVonage & Linksys Offer Trade-In Program Monday, June 13 @ 09:22:36 PDT Vonage is offering customers a way to get a free 802.11g router when they turn in their old one. advertising For a limited time, customers can trade-in their used router any brand, any model for a Linksys Wireless-G Router with 2 Phone Jacks for broadband telephony (WRTP54G) for free (after rebates), when they si........
  • Adventures in pre-paid SIM Cards and data GPRS/Edge/3G in China with China Mobile in Shenzhen, Guangzhou, Shanghai, Beijing and other cities


    This really is a difficult and confusing process for non-Mandarin speakers, but here's what I've done and learned so far: You can purchase an "M-Zone" China Mobile pre-paid SIM Card from almost anywhere but I tried to purchase mine from Suning (a large electronics dealer) hoping they would be able to help me or answer my questions but my plan didn't work out at all.  At Suning once I found someone who spoke some English they gave me the 55 RMB M-Zone China Mobile P........
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