Ubuntu

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Installing Zlib in Ubuntu 22.04

Zlib is a popular open-source compression library used by many software applications to compress and decompress data. It provides fast and efficient compression and decompression algorithms that can be used to reduce the size of data, which can improve performance and reduce storage requirements. In this post, we will discuss how to install zlib in…

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Running Ephemeral Docker Containers – Automatically Remove a Docker Container After Running It

Docker is a convenient tool to quick create containers from different Linux images. If we use the common way to start a docker container like docker run image bash, after the the process exists, the container is still stored there. That is, the docker container persists after it has exited. Sometimes, we would like to…

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Configuring Fonts for Thunderbird snap to Display Fonts Nicely

snap is a software app bundle with dependencies included so that it can works in different Linux distributions. However, as most other software, snap has compatiblity issues. An app in the snap format is not 100% the same and compatible with the native version. One of the problem I find is that Thunderbird from snap…

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Printing Comments in Page Margins in LibreOffice

“Comments” and “tracking changes” are nice features of the opensource LibreOffice software (and other Office software) to add comments and track changes in documents. OpenDocument ODT and MS Word DOCX/DOC file formats all support comments and change trackings. When we print the documents, how to print the comments in the page margins too in LibreOffice?…

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Installing R and RStudio Server in Ubuntu Linux

R is a language and environment for statistical computing and graphics, providing a wide variety of statistical and graphical techniques. The R environment is open source software under GPL. R has rich software packages and is widely used for statistical analysis. RStudio Server is an R integrated development environment (IDE) that provides many useful features…

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Linux Kernel 4.19.70 Release

This post summarizes new features, bugfixes and changes in Linux kernel release 4.19.70. Linux 4.19.70 Release contains 95 changes, patches or new features. In total, there are 101,521 lines of Linux source code changed/added in Linux 4.19.70 release compared to Linux 4.19 release. To view the source code of Linux 4.19.70 kernel release online, please…

Compress PNG Images on Linux

PNG images already use DEFLATE data compression algorithm involving a combination of LZ77 and Huffman coding. But the PNG images can be further compressed by removing non-important metadata or using lossy compression to save storage space and/or data transfer bandwidth. In this post, we introduce 2 compression ways with tools available on Linux. Lossless compression…

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How to Query Transaction By ID in Hyperledger Fabric 2.0

Querying transaction content out from a blockchain network is a common practice used by common scenarios like exploring the blockchain history or verifying the blockchain transaction content from a known ID. In Hyperledger Fabric, the transaction can be queried using a special system chaincode QSCC (Query System Chaincode) which is for ledger and other Fabric-related…

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How to Install Hyperledger Fabric 2.0 in Ubuntu 18.04

Hyperledger Fabric is a consortium blockchain system. It’s performance is relatively good and its modular architecture enables it to be usable in many scenarios. Hyperledger Fabric itself has rich documents and samples of test networks. For beginners, deploying a new network for trying and testing still consumes quite some time. In this post, we will…

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How to list and start VirtualBox VMs in command line in Linux?

VirtualBox is a nice open source virtual machine software. It works nicely on Linux and is supported by many Linux distros like Ubuntu in their official package repositories, so it is quite easy to set it up on Linux. The VMs can also be managed in command line using the vboxmanage command line tool provided…

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How to synchronize OneDrive and OneDrive for Business files in Linux using Insync

OneDrive is one of the good cloud storage services available and there is a business version called OneDrive for Business. Microsoft’s Office 365 plan is widely used including Exchange Email service and OneDrive for Business. However, there is no official client released yet for Linux users. Insync is a third party cloud storage syncing software…

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

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

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…