How to Cat a Text File Out from a Tar Archive You don’t need to fully extract a .tar archive just to read one small file inside it. The tar command allows you to “stream” a single file to your terminal. The Command tar -xOf archive.tar path/to/file.txt -x: Extract -O: Write to standard output (stdout)…
How to Mirror a Website Using Wget on Linux Wget is a powerful command-line utility for downloading files from the web. “Mirroring” a site means downloading its entire structure, including HTML, images, and CSS, for offline viewing. The Command wget –mirror –convert-links –adjust-extension –page-requisites –no-parent https://example.com Breakdown of Flags –mirror: Turns on recursion and time-stamping….
The world of technology has evolved drastically over the last few decades. Almost every aspect of our lives is dominated by technology. At the heart of technology lies computer programming. Computer programming is what dictates the success of the technology. I mean think about it, your smartphone, PC, ETC they all rely on programming. This…
Linux is the most used and well-known open-source operating system for computers, mobile devices, servers, and mainframes, etc. Linux has so many awesome features to serve its users like Live CD/USB. And it is fast, easy and free to use by computers around the world. The kernel is referred to as the essential component of…
How to Write to a Remote Server with Sudo in Rsync By default, rsync connects as your standard user. If you need to write to a protected directory (like /etc or /var/www), you need to use rsync‘s –rsync-path option to run it with sudo. The Command rsync -avz –rsync-path=”sudo rsync” local-file user@remote:/protected/path How It Works…
How to Write File Content with Sudo in Vim We’ve all been there: you spend 20 minutes editing a system configuration file in Vim, only to realize when you try to save (:w) that you forgot to open it with sudo. The “Magic” Command Instead of quitting and losing your work, you can save the…
How to do screen recording on Wayland in Linux? Many screen recorders do not work on the new Wayland. Using Green Recorder You may try Green Recorder which supports Wayland. Note: Green Recorder is no longer under development by the original author (Please check the project README for more details). It still works well for…
It is common that the root disk space is not enough when running a Virtual Machine in the cloud such as Amazon Web Service (AWS). The cloud storage usually provides tools or facilities to enlarge a virtual disk size. However, to make the Linux recognize and and use the enlarged disks without rebooting the OS,…
How to Get Date and Time from Another Timezone in Linux The date command is one of the most versatile tools in a Linux sysadmin’s toolkit. You don’t need external tools to convert timezones; you can do it directly in your shell. The Modern Way: TZ Environment Variable TZ=’America/New_York’ date This temporarily sets the timezone…
Zlib is a widely-used open-source compression library that implements the DEFLATE algorithm. It underpins gzip, PNG, HTTP compression, and countless software packages. While Ubuntu’s package manager provides a ready-to-use zlib, building from source gives you the latest version, the ability to set a custom install prefix, and full control over compile-time options. This guide covers…
Sparse files are common in Linux/Unix and are also supported by Windows (e.g. NTFS) and macOSes (e.g. HFS+). Sparse files uses storage efficiently when the files have a lot of holes (contiguous ranges of bytes having the value of zero) by storing only metadata for the holes instead of using real disk blocks. They are…
We may want to add some swap space for a Linux box while only find that all disk space is partitioned and mounted. Some partition has large available free space. For such cases, we may not want to change the partition allocation. The solution may be to add a file based swap for Linux as…
How to Produce a Patch File for a Git Commit Sharing a single commit as a patch file is a common workflow in open-source projects or when email-based code review is required. The Command git format-patch -1 <commit-hash> This creates a .patch file that includes the commit message, author info, and the diff. Applying the…
The problem is with ssh that makes a quoted string to more than one if there are spaces. For example, ssh user@host cmd “my string” The cmd on host will be executed like cmd my string rather than cmd “my string” It will only work if the string is escaped like ssh user@host cmd my…
How to Get the Canonical File Name in Python (readlink -m) The Linux command readlink -m resolves a path to its absolute, canonical form, following all symlinks and resolving .. or . components. In Python, we have a direct equivalent. The Python Equivalent: os.path.realpath() import os canonical_path = os.path.realpath(“./../folder/./file.txt”) The Modern pathlib Way from pathlib…
How to operator[] access element in a const map in C++? For example, the compiler will report error on this piece of code: #include <iostream> #include <string> #include <map> std::int64_t count(const std::map<std::string, std::int64_t>& map) { return map[“one”] + map[“two”]; } int main () { std::map<std::string, std::int64_t> map = { {“one”, 1}, {“two”, 2} }; std::cout…
How to list start and end of a partition by the sectors in parted on Linux? The default behavior seems be listing the start and end by bytes in parted. # parted /dev/sdc print Model: Innostor IS888 ext. HDD (scsi) Disk /dev/sdc: 2000GB Sector size (logical/physical): 512B/512B Partition Table: gpt Disk Flags: Number Start End…
How to Search Bash History Effectively The “Up Arrow” is slow. In 2026, every power user relies on incremental history search to recall complex commands from the past. The Magic Shortcut: Ctrl + R Press Ctrl + R. Start typing a keyword from the command you remember (e.g., “docker”). Bash will show the most recent…
How To Judge Whether Its Stderr Is Redirected To A File In A Bash Script On Linux Bash remains the default shell for most Linux distributions and macOS systems. While newer shells like Zsh and Fish offer enhanced interactivity, Bash’s ubiquity makes it essential for system administration and CI/CD pipelines. The Modern Approach In modern…
Login without PWD is fast and efficient. Running commands in server from local machine also have these benefits. login without PWD: add PC A’s public key to PC B’s authorized keys. > a@A:~> cat .ssh/id_rsa.pub | ssh b@B ‘cat >> .ssh/authorized_keys’ > b@B’s password: Run command remotely ssh root@MachineB “ls” NOTE: running commands remotely is…