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LFCA 14 🐧 Creating Files and Directories — touch, mkdir
Everything on a Linux filesystem starts as a file or a directory. Directories are the containers; files are the content. Two commands create them: mkdir makes directories, touch creates empty files (or updates timestamps). They’re the first step in almost every workflow — you need somewhere to put files, and you need files to put…
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LFCE 14 🐧 Static Routing — Concepts
Static routing is the manual configuration of a path through a network. An administrator tells the kernel: “To reach this destination network, send packets to this gateway, or out this interface.” The kernel stores that instruction in its routing table, and every packet destined for that network follows it until the route is removed or…
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LFCS 14 🐧 Editing Files with nano
A system administrator edits configuration files. The edit is often a single line, a value, a directive. The editor should be simple, available, and fast. The nano is the editor that meets the criteria. It is installed by default on most distributions, it displays the keyboard shortcuts on the screen, and it does not require…
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Linux CLI 14 🐧 echo command
echo is one of the simplest yet most versatile commands. It displays text, expands wildcards, evaluates variables, does basic arithmetic, and even interprets escape sequences. Basic Usage Output: echo is used to display one or more lines of text to the terminal. Key points: Multiple Arguments Note: echo collapses multiple spaces into one when using…
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Bash Scripting 15 🐧 Return Values — Handling exit status codes ($?) and function outputs
Every command in Bash returns a number between 0 and 255 when it finishes. That number is the exit status, and it is the mechanism by which commands, functions, and scripts communicate success or failure to their caller. The previous chapter covered functions and the return command; this chapter covers the exit status in detail:…
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LFCA 15 🐧 Copying Files and Directories — cp
cp copies files and directories. It reads the source, writes a new copy at the destination, and leaves the original untouched. It’s one of the commands you’ll use most often — duplicating configs before editing, backing up files, moving data into a project directory, populating a template. On the surface it’s simple: cp SOURCE DEST….
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LFCE 15 🐧 Static Routes — Configuration
Configuration is where static routing theory becomes kernel state. The previous chapter established why static routes exist and how the kernel selects them by longest prefix match. This chapter is the operational counterpart: the exact commands to add, verify, replace, and remove routes, the flags that handle gateways outside connected subnets, and the persistence mechanisms…
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LFCS 15 🐧 Editing Files with vim — Basics
The vim is the editor that is installed on every Linux system. It is the editor that the visudo, the crontab -e, and the many other tools open by default. It is the editor that the system administrator must know, because the alternative is the editor that may not be installed. The vim is modal:…
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Linux CLI 15 🐧 shortcuts
Mastering keyboard shortcuts is the fastest way to boost your productivity in the terminal. Once these become muscle memory, you’ll navigate and edit commands at lightning speed — without ever touching the arrow keys. Moving Around the Line Shortcut Action Ctrl + A Move cursor to the beginning of the line Ctrl + E Move…