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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Category: Tutorial
Why std::vector is the Optimal Choice for Data Structures for Performance in C++
Posted onIn C++ programming, data structures are essential for organizing and manipulating data. When it comes to storing and manipulating data, one data structure stands out above the rest – the std::vector. Efficient Memory Allocation One of the primary benefits of std::vector is its efficient memory allocation. std::vector uses contiguous memory allocation, which means that the
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Generating ECDSA K1 and R1 keys using OpenSSL in Linux
Posted onECDSA keys are commonly used in various areas like blockchains. OpenSSL is a commonly used tools in Linux for handling signature/encryption/decryption. This post introduces how to generate ECDSA keys using OpenSSL in Linux. Generate keys for K1 secp256k1 elliptic curve We start with K1 (secp256k1) as the example. To generae ECDSA keys using other curves,
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Sorting Two Lists Together According to The Order of One List in Python
Posted onWe may use two lists to store the values of two properties of a list of elements in Python. Under such data structure arrangement, when we need to sort the properties from one list, we may want to also make sure the other list will be also re-ordered following the same order as the first
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Synchronizing Thunderbird Calendar with Apple iCloud Calendar
Posted onThunderbird is a nice email client and calendar management software. iCloud calendar is the native calendar cloud service in Apple devices such as iPhone. So far there is no native support from Thunderbird to support iCloud calendar, excepting reading the read-only public iCloud calendars which has privacy concerns as long as lacks of editing functionalities.
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SPF, DKIM and DMARC to Stop Email Sender Fraud: Intro and How to
Posted onEmail sender fraud is an annoying problem. Malicious email senders send spam emails with email senders that are under non-authorized domain names. This may affect the reputation of the domains used by the fraud sender. On another hand, lots emails will be rejected and reverted back, which causes lots additional work to the domain administrators.
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Running Ephemeral Docker Containers – Automatically Remove a Docker Container After Running It
Posted onDocker 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
Posted onsnap 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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Starting Page Number from the Second Page in MS Word
Posted onFor document, we may use the first page as the title page. Then the page number 1 should start from the second page. In this post, we will look at how to make MS Word count the page number from the second page. That is, making word treat the second page as page number 1.
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GNONE 3 Screenshot Keyboard Shortcuts
Posted onGNONE 3 provides screenshot tools and utils and also provides keyboard shortcuts which are convenient and quick to use. With the GNOME 3 screenshot keyboard shortcuts, users can make screenshots without having to open the Screenshot app. In general, there are 2 major categories of screenshot shortcuts: those to save the screenshot as a file,
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Reading JSON from URL in R
Posted onR is good at analyzing data. Many data are provided as JSON from RESTful APIs with an URL. R natively support many data format. For JSON, we can use some libraries. For reading JSON from URL, we can use the “jsonlite” package. In this example, we use an example of fetching BTC prices of last
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Reading Excel xls/xlsx Files in R
Posted onMany useful data are stored in Excel xls or xlsx format files. R is good at doing analysis on top of data. We would then need to import the data to R by reading the xls/xlsx files to be R data frames. In this post, we check how to import data from Excel files to
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3 Ways of .odt to .txt File Conversion in Command Line in Linux
Posted onThe Open Document .odt files can contain rich formats for the content. However, some times a plain text file is more handy. We may convert .odt files to plain text files for such needs. In this post, we discuss 3 ways of how to convert .odt files to .text files in command line in Linux.
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.docx/.doc to .odt File Conversion in Command Line in Linux
Posted onWord .docx and .doc files are common for documents commonly generated by MS Word software. We would like to convert them to the more open ODF Open Document .odt files for various cases. This can be done by GUI software tools. If we have a set of many .docx/.doc files, it will be handy if
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Configuring Eclipse to Show Git Revision Information Similar to Git Blame in Editor
Posted onEclipse can work well with Git. We discussed Configuring Eclipse to Highlight Changed Lines Compared to Git Commit before. Eclipse can also show the revision information for lines of code (from git blame) which is useful to understand why some lines are added in the context of previous revisions including the lines of code. Eclipse
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2 Ways of Modifying macOS Keyboard’s Right Option to Control for Mac Pro
Posted onFor heavy Terminal/Shell/command line users, the Control key is a very frequently used key. However, in Mac Pro keyboard, there is only a single left Control key for some models. This cause quite some inconvenience. In this post, we will go through how to configure/remap the keys to “create” a right Control key. Remap keys
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Converting Hex to ASCII Using xxd
Posted onStrings are commonly encoded as hexadecimal (hex) strings for various purposes. Hence, it is also common to convert hex strings to its original strings such as an ASCII string. Hex to ASCII string conversion can be done programmatically in many languages. In command line, we can use xxd to convert hex to ASCII string. This
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Release Notes For Linux v2.0
Posted onThis is the release notes for linux release v2.0 (source code: linux-2.0.tar.gz) with format adjusted by removing/replacing tabs/spaces/new lines/formatting marks. This notes document can give us an understanding of the early development of the Linux kernel. The original ASCII formatted version is at the end of this post. Intro This document contains a list of
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Release Notes For Linux v0.95
Posted onThis is the release notes for linux release v0.95 (source code: linux-0.95.tar.gz) with format adjusted by removing/replacing tabs/spaces/new lines. This notes document can give us an understanding of the early development of the Linux kernel. The original ASCII formatted version is at the end of this post. RELEASE NOTES FOR LINUX v0.95 Linus Torvalds, March
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Configuring Eclipse to Highlight Changed Lines Compared to Git Commit
Posted onEclipse is one of the good IDEs for C/C++ projects with its great source code indexer. It is common the source code version is controlled by some tools like Git for software projects. It is convenient if the IDE can show the current changes compared to the committed code version. In this post, we will
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