DEV Community: Alexander Njoku

https://medium.com/@alex2020global/file-editors-operations-in-linux-cdfa8cd7fbda

Alexander Njoku — Sat, 12 Jul 2025 04:47:01 +0000

Linux provides various command-line and graphical text editors for file manipulation. Common command-line editors include nano, vi/vim. These tools allow users to create, open, edit, and save files.

In this practice, I will use vi because I personally prefer vi than nano

To use vi

Type vi and filename you want to edit

Press Enter

If I want to start writing or editing the contents I will first of all Press (i)

insert then I will start writing or editing after which I will Press (esc) key

(:) Colon

(w) Write

(q) Quit

(!) Bang

Then Press Enter

That takes you back. Then if you want to see or view the contents of what you have written or edited use (cat)

(cat) — Concatenate — It is used to quickly view the content of one or more files directly in the terminal, it can also be used to merge file and its contents into another file.

(cat) — Concatenate- To merge and create a file and its contents into another file.

echo- This is used to create a file, write a file and over write the contents in an existing file.

vi Editing Commands
Command Description
i Insert at cursor (goes into insert mode)
a Write after cursor (goes into insert mode)
A Write at the end of line (goes into insert mode)
ESC Terminate insert mode
u Undo last change
U Undo all changes to the entire line
o Open a new line (goes into insert mode)
dd Delete line
3dd Delete 3 lines
D Delete contents of line after the cursor
C Delete contents of a line after the cursor and insert new text. Press
ESC key to end insertion.
dw Delete word
4dw Delete 4 words
cw Change word
x Delete character at the cursor
r Replace character
R Overwrite characters from cursor onward
s Substitute one character under cursor continue to insert
S Substitute entire line and begin to insert at the beginning of the line
~ Change case of individual character

https://medium.com/@alex2020global/file-viewing-inspection-8530aa17b64f

Alexander Njoku — Sat, 12 Jul 2025 04:46:11 +0000

In Linux, files can be viewed and inspected using various command-line tools. cat, head, tail, less, and file are commonly used for displaying file contents and determining file types.

 less: View file contents interactively (scrollable).

 less file.txt: Open a file for reading.

 head/tail: View the start or end of a file.

 head -n 10 file.txt: Show first 10 lines.

 tail -f file.log: Monitor a log file in real-time.

 file: Determine a file’s type.

 file filename: Identify file format (e.g., text, binary).

https://medium.com/@alex2020global/compression-archives-files-in-linux-780d08183761

Alexander Njoku — Sat, 12 Jul 2025 04:44:39 +0000

In Linux, archiving and compression are distinct but often used together to manage files efficiently. Archiving combines multiple files and directories into a single archive file, while compression reduces the file size for storage and transfer. This will optimize costs in your company.

Creating archives with tar: gzip can’t add multiple files into one archive, hence we use the tar

program.

c — create

v — tell the program to be verbose and let us see what it is doing

f — the filename of the tar file has to come after this option

tar -cvf file3.txt.tar file3.txt

Then to achive files and directories

tar -cvf archive.tar list the files and directories

Then to archive files and directories

tar -cvf archive.tar list the files and directories

tar xvf text.txt.tar

To extract a tarred file

: $ tar xvf archive.tar

List the files in a tarred file

Zip and unzip files (Before you do this make sure that there’s zip apt in your system)

tar -czvf lesson.js.tar.zp
gzip/gunzip: Compress/decompress files.
gzip file.txt: Compress to file.txt.gz.
gunzip file.txt.gz: Decompress.
zip/unzip: Work with ZIP archives.
zip archive.zip file.txt: Create a ZIP file.
unzip archive.zip: Extract a ZIP file.

https://medium.com/@alex2020global/filesystem-navigation-in-linux-aabaa87e8029

Alexander Njoku — Thu, 10 Jul 2025 16:10:32 +0000

This week I focused on Filesystem Navigation

What is filesystem navigation? Filesystem Navigation in Linux refers to the process of moving between different directories and files within the hierarchical file system using commands in the terminal. Is how users local and access the data stored on the system. Key to the process is understanding the single, root-based structure of the Linux filesystem, where everything branches from the / (root) directory.

Key takeaways:

Hierarchical structure
Current working directory
Paths- Specify the sequence of directories to traverse to reach a specific file or directory, they can be absolute (starting from the root) or relative (starting from the current directory).
Absolute paths- Start with / and specify the full path from the root
Relative paths- Specify the path relative to your current location

Before I dive in to the command is important to establish this fact; anytime you come to a system and see this sign (#) instead of ($) just know that you are in the root directory and you must be very careful here.

Flags, also known as options or switches, are used to modify the behavior of commands. They are typically preceded by a hyphen (-) or a double hyphen ( — ), and are used to specify options or provide additional instructions when executing a command.

ls: List directory contents, display a list of files and directories within your current working directory

ls -l: This will show a long information about a directory, date they were created, time, permission attached to it, group, owner and other details.

ls -a This will list hidden files

Note: Whenever you want to hide a file in linux start it with (.) dot.

ls -R Recursively list subdirectories, that means including the contents of all subdirectories and their subdirectories and so on.

ls — color=auto: To display colours and change colours

Note: (alias:) When you have a command that is too long you can create an alias for it instead of typing the long phrase, alias can be in one word, it is used to shorten commands.

cd: You use cd to change directory and also go straight to a file path direct when you copy the path.

cd../.. This will display your two steps backwards

You can use arrows in your keyboard to do this

Upper arrow key — Precious command

cd — This will tell you where you are

 cd ..: Move up one directory.

 cd ~: Return to the home directory.

 cd -: Return to the previous directory

 cd ../..: Return to two directories backward

Note:- If you want to see all the commands you have run in a system Type: History this will display all the commands you have run.

pwd: Print the current working directory

whoami: command in Linux is used to display the effective username of the currently logged-in user

mkdir: Make a directory

mkdir dir_name: Create a single directory

mkdir -p dir1/dir2: Create nested directories. (Note) Nested directories, also known as subdirectories or hierarchical directories, are a fundamental way to organize files and directories in Linux.

rmdir: Remove an empty directory. This will remove an empty directory

 rmdir dir_name: Delete a directory (only if is empty).

 rm -r: Remove a directory and its contents.

 rm -r dir_name: Recursively delete a directory and all files/subdirectories.

mv: We use it in linux to move a file or directory

mv: We can also use it to rename a file or directory

Is also important to note that (Home directory) houses all the users in that server if what to see the users you are working with go to home.

Also keep in mind that you Linux can help you in many ways to explain things in details all you just need to do is type (man) in front of anything that you are confused about lets say i want to know more about (ls) i will just type :man ls

Thanks for sticking with me in this beautiful journey from Linux to DevOps Engineer, next I will go into File Operations, If there’s anything you want to share, ask, plan, or work through next — just let me know. Alex

https://medium.com/@alex2020global/understanding-the-linux-filesystem-92e2eb65968f

Alexander Njoku — Sat, 05 Jul 2025 17:27:40 +0000

Understanding the Linux Filesystem
As promised in my last article this week I focused on Linux Filesystem Structure.
The Linux file system is hierarchical, starting from the root directory (/) and branching out into subdirectories.

Key directories in the Linux Filesystem

/ (root) directory --> Root directory; the top-level directory of the file system, it’s worth noting that only the root user possesses the privilege to execute write operations within this directory. To see the files inside the root directory you have go as a superuser sudo su and cd into it, type ls and Press enter.

/bin directory --> Within the '/bin' directory, you'll find a collection of binary executable files needed for booting and system recovery. According to Mr Bernard Chika Uwaezuoke "Binary files are fundamentally composed of a sequence of bytes, each represented by a combination of 0s and 1s".

/boot directory --> Files required for booting the system (e.g., kernel, bootloader). Please DO NOT TOUCH files here you may mess up your system.

/dev directory --> Device files representing hardware devices, such as 'cdrom,'web cam’ 'cpu,' printers, USB, and more. this is a place to check Hardware issues. Drives of external hardware devices are here.

/etc directory --> Configuration files for the system and installed software, it houses the fundamental configuration files that are vital for the system's operation. This is a place to check software issues. It's System Administrators and DevOps professionals who handle these files. They encompass a wide range of configurations, such as usernames, passwords, network settings, application-specific configurations, as well as system startup and shutdown scripts.

/home directory --> User-specific directories and files, whenever a new user account is created, a corresponding directory bearing their username is automatically generated within the home directory to provide them with a dedicated storage space.

/lib directory --> Shared libraries required by system programs, it house shared library files crucial for booting the system, functioning much like DLLs on Windows. '/lib' accommodates 32-bit compatibility libraries. Applications need them to function.

/media directory --> Mount points for removable media (e.g., USB drives, CDs), Any external storage such as media/cdrom when plugged in will be automatically mounted under /media directory. When you have issues with USB, speakers and any external hardware this is a place to check.
It is empty because I haven’t connected anything yet.

/mnt directory --> Temporary mount points for external file systems, (Hardware, storage) This directory serves as a location where system administrators can mount regular filesystems like NFS. Is here that you add more storage (Eg) When you purchase a gigabyte from AWS or any other vendor this is the place where you mount and format it so that it will be permanent/persistence because if is not persistence when you reboot your system it will go away.
It is empty because I have not mounted anything.

/opt directory --> Optional add-on software packages, this directory contains any third-party applications available from individual vendors. It is recommended to install third-party applications under /opt. You can add plugins and extensions here.
No extensions yet.
/proc directory --> Virtual file system providing information about system processes, this directory stores data related to system processes identified by a specific process ID (PID). It's commonly referred to as a virtual or pseudo filesystem, as it contains textual information about various system resources, including CPU and memory. Files and directories within this directory are generated dynamically as the system starts or undergoes changes. The current process that are running in the system the information this is a place to see them.

/root directory --> Home directory for the root user, anytime you come to system and see # sign instead of $ sign just know you are in the root directory. BE CAREFUL HERE. If you don’t have privileged you can’t enter to root directory.

/run directory --> Runtime variable data, This directory is designed to contain temporary data that does not need to persist across system reboots. Variables are like creating a vacant room that does not have anything, anytime you want to use it you can put anything inside it, variables are place holders. If you having issues with runtime variables files you have to check here. /run

/sbin directory --> System binaries used for system administration, it contains essential executable programs for system administration and maintenance, primarily used by the root user and requiring root privileges for execution. This contrasts with /bin and /usr/bin, which hold user-level executables, and /usr/sbin, which also contains system administration binaries but are typically needed after the /usr filesystem is mounted during system startup.

/srv directory --> Data for services provided by the system, to see services and configurations of a server.
No server is configured yet.
/tmp directory --> Temporary files, many applications keep their temporary files here which contain data that an application might not need right now but may need later. These files will be kept until the next boot or application restart.

/usr directory --> Secondary hierarchy for user-related data, this directory contains applications, libraries, docs, icons, images and other files which needs to be shared by applications and services. It is basically shareable, read-only data.

/var directory --> Variable data such as logs, caches, and spool files, the index files of a webserver are located in /var, it stores variable data files, meaning files that are expected to grow or change during normal system operation.

This is what I learned this week (July 01- 05, 2025) next week I will focus on Filesystem Navigation.

Thanks for following my journey from Linux to DevOps. Alex

Linux Explain (Journey from Linux to DevOps)

Alexander Njoku — Sun, 29 Jun 2025 23:40:59 +0000

History of Linux: -
Linus Torvalds started working on Linux as a replacement to the Minix OS while at the University of Helsinki in Finland. Torvalds recognized the work done on the GNU Project in 1983, which intended to create a complete, Unix-compatible OS comprised entirely of free software, and noted the GNU as a model for distribution. However, the work on GNU had not been finished by the time Torvalds sought a Minix replacement, prompting him to develop an alternate OS kernel dubbed Linux -- a contraction of Linus' Unix -- and adopt the GNU GPL.

Torvalds released the Linux kernel in September 1991. A community of developers worked to integrate GNU components with Torvalds' kernel to create a complete, free OS known collectively as Linux. Torvalds continues to develop the Linux kernel and a vast developer community continues to create and integrate a wide range of components.

While Linux still lags Windows and macOS on the desktop, it continues to challenge the proprietary OS vendors on servers and embedded systems.

Linux is a family of open-source Unix-like operating systems, built around the Linux kernel. It's known for its flexibility, security, and use in a wide range of devices, from smartphones to supercomputers. It's commonly distributed as a Linux distribution, which includes the kernel and other essential software.

Open source software. The Linux kernel is released under the GNU GPL open-source software license. Most distros include hundreds of applications, with many options in almost every category. Many distributions also include proprietary software, such as device drivers provided by manufacturers, to support their hardware.
Licensing costs. Unlike Microsoft Windows or Apple macOS, Linux has no explicit licensing fees. While system support is available for a fee from many Linux vendors, the OS itself is free to copy and use. Some IT organizations have increased their savings by switching their server software from a commercial OS to Linux.
Reliability. Linux is considered a reliable OS and is well-supported with security patches. Linux is also considered to be stable, meaning it can run in most circumstances. Linux also copes with errors when running software and unexpected input.
Backward compatibility. Linux and other open source software tend to be updated frequently for security and functional patches, while retaining core functionality. Configurations and shell scripts are likely to work unchanged even when software updates are applied. Unlike commercial software vendors that roll out new versions of their OSes along with new ways to work, Linux and open source applications generally don't change their modes of operation with new releases.
Many choices. Between the hundreds of available distributions, thousands of applications and almost infinite options for configuring, compiling and running Linux on almost any hardware platform, it is possible to optimize Linux for almost any application.

Key functions of Linux:-
Hardware Management
Server Operations
Software Development
Embedded Systems and IoT
Cloud Computing
Desktop Computing
Networking
Multi-user and Multitasking
Security and Customization

Types of Linux
Debian
Fedora
Ubuntu
Red Hat Enterprise Linux

openSUSE
Linux Mint
Arch Linux
CentOS
Elementary OS

How to download Linux: -
First you have to check your system security and configuration, turn Windows features on or off screen will open up, scroll to where you have Windows Subsystem for Linux and check the dialog box beside it, then choose the version of Linux you want to download; Ubutu releases a new version every six months; whereas, Long Term Support versions (LTS) are released every two years, go to Microsoft store choose the version and click get it will start downloading after that you click install and open. Double-click on the setup file to install it and click Next, When prompted for user access permission, click on Yes to continue and then click on Finish to complete the installation.
After that you install the Windows Terminal:-
search for it on the Microsoft Store on your PC. Click on get to download it and then click on open to open it after the installation.
You will be able to switch tabs rapidly and move between various Linux distributions or other command lines (PowerShell, Command Prompt, Azure CLI, etc), I was able to install Linux, Wsl in VS Code.

Note:- I dive into Bash scripting and its importance in a production. Bash shell scripting refers to the practice of writing sequences of commands for the Bourne-Again Shell (Bash), a widely used command-line interpreter in Unix-like operating systems like Linux and macOS. These sequences of commands are stored in a plain text file, known as a Bash script, and are executed by the Bash interpreter. Most importantly I learnt how to install Screenespresso, which is use to capture desktop (screenshots and HD videos) for training documents, collaborative design work, IT bug reports.

This is what I learned this week (June 23-27, 2025) next week I will focus on Linux system files and commands. – Alex

Linux to DevOps journey

Alexander Njoku — Sat, 28 Jun 2025 20:31:47 +0000

Introductory Article:
Firstly, my name is Alexander Njoku (Alex) rightly put I have always been a tech person, I took my first six-months training in tech immediately after my high school in 1997 graduated within 4months; has worked in many big organizations as a Graphics/creative designer, Automation engineer, started with CorelDRAW 6 in Windows 95. I remembered one unforgettable event that happened during 1999 when it was predicted that computers will shoot down in January 2000, Millennium burg or Y2K we all slept in the office that night and was so anxious to witness but nothing to the systems at the end of the day.

It feels good to be here in Dev.to though I’m new trust me I will be writing and blogging as somebody that has been here for years my articles will mainly focused on a beautiful journey from Linux to being a DevOps Engineer, I will keep updates of the steps accordingly it might be days apart or weekly but I promise it will be entertaining and also educative it will help people without tech experience, businesses, companies and those that wants to level up their skills in Linux, Aws, Azure, Python, Bash, Git, GitHub/GitLab, Terraform, Kubernetes, Jenkins, CI/CD, DevOps etc.

I’m a honest person, always stick to my word; family oriented man, grew up in the house of boys, love travelling so much recently made it to 18 states and 32 cities here in the United States still counting, soccer is my favorite hobby Americans call it football, I love listening to Bob Marley’s music but when I want to hear the atrocities that happened in Nigeria in the 60’s, 70’s and 80’s I switch to Fela Anikulapo Kuti, Osita Osadebe and Oliver De coque are two great musicians from Igboland in their songs they mention respected Igbo businessmen and elders with their title in their praise signing style, one of Osadebe’s popular songs in recordings is “Osondi Owendi medley or Onuigbo special. In Christian songs I grew up with Agepe love band by Isreal Anyamele, it just came to my attention few months ago that he has raised a son who is a gospel artist too. Yossundor from Senegal is another great musician you should check him out. In all Davido is my guy after Don Jazzy slowdown in his musical career, Jay-Z and Rick Ross makes good music too.

Having said this, I will conclude by advising my readers to stay close to this page so as so get all the updates of the journey from Linux to DevOps Engineer, in my next article I will explain Linux very well.

Thanks for being a good reader please come back again.

Alex