Generating a Pair of RSA Private and Public Keys in Linux using OpenSSL

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RSA (Rivest–Shamir–Adleman) is a widely used public-key cryptosystem that is used for secure communication over the internet. In this post, we will explore how to generate a pair of RSA private and public keys in Linux using the OpenSSL library. Generating a pair of RSA private and public keys in Linux using OpenSSL is a
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How to Statically Link OCaml Programs

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Static linking is preferred for some cases although it has its own various problems. Static building/linking is not always possible for some languages on some platform. For OCaml, the answer to this question is yes. In this post, we will introduce 2 methods to statically linking OCaml: static linking with runtime glibc required and static
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How to add Chinese input method to Unbuntu 18.04?

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How to add Chinese input method, such as Pinyin, to Unbuntu 18.04? To input Chinese, first install an input method framework. Here, we use fcitx. Then you need to input the Pinyin input method. You may use fcitx-sunpinyin. Put them all together $ sudo apt-get install fcitx fcitx-sunpinyin After that, set the default input method
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How to get a server’s serial number remotely?

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How to get a server’s serial number remotely? Tested on Linux Ubuntu 14.04 Trusty > sudo apt-get install dmidecode > sudo dmidecode -s system-serial-number I tried this on several Linux boxes with CentOS 7 and it seems A physical node returns a string like System Serial Number. A KVM VM returns a string like 3fd12bba-12d4-48c7-875a-7a5f57ed8a9a.
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Libvirt crash when upgrade from version 1.2.2 to version 2.5.0

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If you install libvirt from ubuntu software library like this sudo apt-get install libvirt-bin The default version is 1.2.2 for Ubuntu Trusty. However, after you upgrade it to version 2.5.0 from its source codes (restart the libvirtd service), you will see following error if you want to install vm with virt-install. # ./installkvm1.sh Starting install…
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Cannot start VM with error “no network with matching name ‘default'”

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I update libvirt version and want to start VM with the new libvirt tools but I failed as follows. > sudo virsh start kvm1 error: Failed to start domain kvm1 error: Network not found: no network with matching name ‘default’ It seems that the default ‘virbr0’ is missing after I update libvirt so I solve
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How to install PARSEC correctly.

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PARSEC is the most important CPU-bound benchmark for systems. It is huge and hard to install because it needs lots of 3-part libs. PARSEC download link for 3.0 version: http://parsec.cs.princeton.edu/download.htm#parsec I remembered I added the answer yesterday night but I could not see the answer currently. Anyway, let me add the answer again after I
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how to install older version gcc/g++ in Ubuntu (other linux distro are similar)

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When we compile some project, it needs older version gcc/g++ version. So how to insall older ones in ubuntu 16? Install older gcc/g++ version sudo apt-get install gcc-4.4 g++-4.4 g++-4.4-multilib gcc-4.4-multilib Set gcc/g++ version to be used automatically sudo update-alternatives –install /usr/bin/gcc gcc /usr/bin/gcc-4.4 50 sudo update-alternatives –install /usr/bin/g++ gcc /usr/bin/g++-4.4 50 You may need
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I cannot login Ubuntu Precise desktop

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I cannot login desktop in Ubuntu Precise. It told me following errors: Could not write bytes: Broken Pipe… Check Battery Satte Actually, I tried many ways to solve this problem. It seems that something wrong with my lightdm software so, at last, I use gdm software to replace lightdm to kill this problem. Just install
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Finding All Available Versions of a Package in Ubuntu

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How to find all available versions of a package in Ubuntu? To list available versions of a package: apt-cache showpkg <package-name> For example, to check all versions of thunderbird: $ sudo apt-cache showpkg thunderbird Package: thunderbird Versions: 1:31.1.1+build1-0ubuntu0.14.04.1 (/var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_trusty-updates_main_binary-amd64_Packages) (/var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_trusty-security_main_binary-amd64_Packages) Description Language: File: /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_trusty_main_binary-amd64_Packages MD5: 68ed1001b79d708ad48956a0c129114d Description Language: en File: /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_trusty_main_i18n_Translation-en MD5: 68ed1001b79d708ad48956a0c129114d 1:31.0+build1-0ubuntu0.14.04.1 (/var/lib/dpkg/status)
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How to find the history of updated packages by apt-get or aptitude?

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How to find the history of updated packages by apt-get or aptitude? The history is in log files of dpkg and apt: /var/log/dpkg.log /var/log/apt/history.log /var/log/aptitude To check the recently installed packages: cat /var/log/dpkg.log | grep ” install ” To list history of recently installed packages by apt-get: cat /var/log/apt/history.log | grep ” install ” To
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How to install ffmpeg on Linux Mint 17 Qiana?

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How to install ffmpeg on Linux Mint 17 Qiana? To install FFmpeg on Ubuntu 14.04 Trusty Tahr, Linux Mint 17 Qiana and etc: $ sudo add-apt-repository ppa:jon-severinsson/ffmpeg $ sudo apt-get update $ sudo apt-get install ffmpeg Does anyone know why this was taken out of the main repositories? Linux Mint 17 is based on Ubuntu
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How to install no-ip update client on Linux Mint?

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How to install no-ip.com update client noip2 on Linux Mint 17? First, install the noip2 client: sudo su – cd /usr/local/src wget http://www.no-ip.com/client/linux/noip-duc-linux.tar.gz tar xzf noip-duc-linux.tar.gz cd no-ip-2.1.9-1 make make install Then, generate the configuration file noip2 -C Last, make noip2 daemon run at reboot crontab -e Add this line to crontab: @reboot /usr/local/bin/noip2 I’ve
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Installing Latex and Compiling a Latex Docuent in Linux

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Latex is a popular document preparation system that is widely used for creating scientific and technical documents. Compiling Latex documents on Linux is a straightforward process that requires only a few Latex packages and a set of commands. By following the steps outlined in this post, you can easily compile Latex documents on your Linux
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How to Configure the Latest Version of Flash on Firefox for Linux: by the Fresh Player Plugin

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As you may know, Adobe stopped supporting the NPAPI version of Flash on Linux and the latest NPAPI version of Flash player at version 11.2 released back in 2012 will only receive security fixes. Even the security fixes to the 11.2 version of the Flash Plugin your Firefox is using will end on May 4,
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Converting Movie Files to wav and mp3 Files Using MPlayer and LAME

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As a multimedia enthusiast, you may want to convert your movie files to audio files for various reasons such as creating soundtracks, audio books or listening to dialogues & music without the video. Converting movie files to WAV and MP3 files using MPlayer and LAME is a simple and straightforward process. By following the steps
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