Category: GNU-Linux

apt yum exclude package from update upgrade

maybe you want to run your own version of the kernel and you will have to prevent during an automatic update that this kernel will get „replaced“. same goes with firefox, thunderbird and LibreOffice yum and apt might not install […]

NMAP basic network scanning – overview over LAN

What computers are online? What services/ports in what versions are online/open? over poorly or not so poorly documented LANs you can get an overview by using nmap. yum install nmap; # centos/redhat apt-get install nmap; # debian/ubuntu # get a […]

Scanning over LAN Network with Linux and Brother 9460 CDN

Brother 9460 CDN is a reliable old Brother LAN enabled Multifunction (MFC, Print, Scan, Fax) device. hardware used: dell laptop E4310 + debian linux 32bit + brother 9460 cdn connected via LAN root@DebianLaptop:~# hostnamectl Static hostname: DebianLaptop Icon name: computer-laptop […]


somtimes it is easier to land on the moon… than install a printer… [root@centos user]# hostnamectl Static hostname: centos.template Icon name: computer-desktop Chassis: desktop Operating System: CentOS Linux 7 (Core) CPE OS Name: cpe:/o:centos:centos:7 Kernel: Linux 4.15.1 Architecture: x86-64 Epson_Stylus_SX510W […]


… i never regret the learning curve of going Open Source. its not easier – but way more solid. order yourself a try without install boot stick today: if it does not boot – money back!

CentOS7 install ntfs support

one partly cloudy day i was trying to copy things via usb stick… it would not work. i realized: i haven’t used NTFS for a while 😀 yum install ntfs-3g fuse replug the stick. you don’t even have to restart […]


who is who? concepts: docker is written in Google Go by Docker Inc, SanFrancisco because it does not emulate any hardware – it is a linux container / sandbox or jail like Free BSD Jail or Solaris Zones. For example […]

linux bash bc – calculating with pi

bc is cool, but it can not access shell variables directly, but you can pass them with <<< also there is no „pi“ constant in bc that you could use in interactive mode. let one assume you would like to […]

gpg verify downloaded software – no public key

if you download software, you should verify that what you downloaded is not a altered file of a hacked server distributing trojan horses and keyloggers (malware). it seems for the gpg verification it is a 3 step process. 1. download […]


on intel / amd cpus/boards: use lm sensors: apt-get install lm-sensors; # install sensors-detect; # detect available temperature sensors, answer with YES usually # monitor cpu temp every second while true; do sensors|grep Core; sleep 1; clear; done; service kmod […]


it is pretty cool… a 32Bit Linux Host can run a 64Bit Linux guest. NICE 😉 i assume you have a working CentOS7 basic installation and are root. tested on/with: tested with: Host: Debian 8 Jessie and CentOS7 Operating System: […]

Thunderbird Icedove Reorder Accounts

first of all – thanks for this cool mail client 🙂 i really love icedove / thunderbird. A very cool feature that i am missing – it’s nice that imap can syn mail accounts – and i really love that […]

VirtualBox under LinuxDebian – Hang Hung VM on Starting Virtual Machine

this applies to: VirtualBox Version 5.1.8 r111374 (Qt5.3.2) hostnamectl Static hostname: DebianWorkstation Operating System: Debian GNU/Linux 8 (jessie) Kernel: Linux 3.16.0-4-686-pae Architecture: x86 the VMs hangs on startup with this screen: Solution: kill the vm then disable audio device… the […]


ome observers might well believe that the kernel has accumulated plenty of special-purpose virtual filesystems. Even so, 2.6.14 will include yet another one: securityfs. This filesystem is meant to be used by security modules, some of which were otherwise creating […]


the mail system is a very broken and corrupted system. sending-addresses can be forged – spam from all over the world is flooding the mailboxes – viruses get attached… nobody trusts attachments anymore. it’s a completely newly C++ developed mailserver […]

Who is THE Urban Penguin?

Andrew Mallett also on twitter apparently… 😀 pretty complete video series on LPIC1 FOR FREE ONLINE ON YOUTUBE 🙂 GOOD JOB MR MALLETT! 🙂 THANKS! LPIC2 not so much… you will have to pay for it 🙂 Andrew is an […]


I believe since you do not know the file name/process id, you could specify user name option as below. lsof -r 2 -u username The „-r 2“ option puts lsof in repeat mode, with updates every 2 seconds. (Ctrl -c […]

CentOS7 Security Profiles and Software Security Flaws TopList

exploits in software toplist: 2017: All time: That is why the Unix Philosophy of small, modular and beautiful matters … maybe that’s why Mr Stallmann prefers Microkernels… but well let’s be happy there is an alternative kernel to […]


the strangest thing about mtr is probably that it seems to work only with a desktop-terminal. not an ssh-terminal 😀 What is MTR? mtr combines the functionality of the ‚traceroute‘ and ‚ping‘ programs in a single network diagnostic tool. As […]


-p, –print-cache Print the lists of directories and candidate libraries stored in the current cache. manpage: manpage – dynamic linker – root@debian9:~# ldconfig -p 664 libs found in cache `/etc/‘ (libc6,x86-64) => /lib/x86_64-linux-gnu/ (libc6,x86-64) => /usr/lib/x86_64-linux-gnu/ […]