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Note: IT Terms & History Dictionary excluded.

C
 An overview of C, features and trade-offs, how execution works (.c → gcc → binary), and a recommended learning order for this dictionary.
C
 Comment syntax in // / /* */, when to write comments, and when not to.
C
 Steps for setting up an environment to compile and run C programs.
C
 How to write, compile, and run .c and .h (header) files.
C
 The program entry point. argc / argv.
C
 Basic data types: integers, characters, and floating-point numbers.
C
 Type qualifiers: signedness, constants, and optimization suppression.
C
 Conditional branching.
C
 Multi-way conditional branching.
C
 Loop constructs.
C
 Declaring, defining, and using function arguments and return values.
C
 Storing elements of the same type sequentially with index access.
C
 Getting addresses and dereferencing pointers.
C
 Array names as pointers and pointer arithmetic.
C
 char arrays, string literals, and null termination.
C
 A data structure that groups different types together.
C
 A data structure that shares the same memory among members.
C
 A group of named integer constants.
C
 Defining type aliases.
C
 Getting the byte size of a type or variable.
C
 Including headers and defining macros.
C
 Function-like macros with arguments and inline expansion.
C
 Conditional compilation and include guards.
C
 Compiler directives and forced errors.
C
 Pointers that store function addresses for callbacks.
C
 Dynamic memory allocation and deallocation (stdlib.h).
C
 Formatted output with format specifiers (stdio.h).
C
 Formatted input (stdio.h).
C
 Character and line-based standard I/O (stdio.h).
C
 Getting string length and copying strings (string.h).
C
 Concatenating strings (string.h).
C
 Comparing strings (string.h).
C
 Searching for substrings and characters (string.h).
C
 Copying, initializing, and comparing memory blocks (string.h).
C
 Converting strings to numbers (stdlib.h).
C
 Integer absolute values and simultaneous quotient/remainder calculation (stdlib.h).
C
 Generating pseudo-random numbers (stdlib.h).
C
 General-purpose sorting and binary search (stdlib.h).
C
 Program termination and registering exit handlers (stdlib.h).
C
 Classifying character types (ctype.h).
C
 Converting between uppercase and lowercase (ctype.h).
C
 Square root, power, absolute value, and rounding (math.h).
C
 Trigonometric and inverse trigonometric functions (math.h).
C
 Logarithmic and exponential functions (math.h).
C
 Floating-point number operations (math.h).
C
 Opening and closing files with mode strings (stdio.h).
C
 Line and character-based text file I/O (stdio.h).
C
 Reading and writing binary files (stdio.h).
C
 File position manipulation and end-of-file detection (stdio.h).
C
 Getting current time and elapsed time (time_t, clock_t) (time.h).
C
 Converting between time_t and struct tm (time.h).
C
 Formatting time as a string (time.h).
C
 Implementing variadic functions (stdarg.h).
C
 Precondition checks for debugging with NDEBUG (assert.h).
Command
 An overview of Bash, its features, and how execution works, along with a recommended learning path through the dictionary.
Command
 Comment syntax in #, when to write comments, and when not to.
Command
 Steps to set up an environment for creating and running Bash scripts.
Command
 How to write and run .sh files.
Command
 Displaying a list of files.
Command
 Navigating directories and checking the current location.
Command
 Copying, moving, and deleting files and directories.
Command
 Creating directories and files.
Command
 Searching for files.
Command
 Creating symbolic links and hard links.
Command
 Changing permissions and ownership.
Command
 Checking file information and disk usage.
Command
 Displaying file contents in order and in reverse.
Command
 Browsing a file with paging.
Command
 Displaying the beginning or end of a file.
Command
 Outputting strings.
Command
 Counting lines and words, sorting, and removing duplicates.
Command
 Searching text for patterns.
Command
 Line-based text substitution and editing.
Command
 Field processing and aggregation of text.
Command
 Cutting, pasting, and joining fields.
Command
 Converting and formatting characters.
Command
 Comparing file differences and applying patches.
Command
 Passing the output of one command to the next.
Command
 Chaining commands with conditional execution.
Command
 Redirecting stdout and stderr.
Command
 Redirecting stdin and using here documents.
Command
 Writing to a file in the middle of a pipe.
Command
 Running commands from a list of arguments.
Command
 Declaring, assigning, and referencing shell variables.
Command
 Setting and checking environment variables.
Command
 Advanced variable expansion and default value settings.
Command
 Special shell variables used in scripts.
Command
 Integer arithmetic.
Command
 Generating sequences and strings.
Command
 Using command output as a value.
Command
 Conditional branching.
Command
 Evaluating conditional expressions.
Command
 Multi-way branching by value.
Command
 Looping over a list or range.
Command
 Conditional loops.
Command
 Generating an interactive menu.
Command
 Basics of shell functions.
Command
 Receiving arguments and returning values.
Command
 Reading from standard input.
Command
 Creating and executing script files.
Command
 Loading another script file.
Command
 Configuring and unsetting shell behavior options.
Command
 Setting and removing command aliases.
Command
 Scheduling recurring tasks.
Command
 Privilege escalation commands.
Command
 Managing command history.
Command
 Syntax of /etc/hosts and using it to resolve hostnames before querying DNS.
Command
 Finding command locations and types.
Command
 Waiting and generating sequences.
Command
 Working with arrays in Bash.
Command
 String manipulation using parameter expansion.
Command
 Parsing script options.
Command
 Dynamic execution and process replacement.
Command
 Managing system services.
Command
 Default permissions for new files.
Command
 Checking running processes.
Command
 Stopping processes and sending signals.
Command
 Running in the background and managing jobs.
Command
 Waiting for processes and catching signals.
Command
 Sending and receiving HTTP requests.
Command
 Downloading files.
Command
 Connecting to remote hosts and transferring files.
Command
 Network diagnostics and name resolution.
Command
 Creating and extracting archives.
Command
 Compressing and extracting files.
Command
 Getting and manipulating dates and times.
Command
 Summary of key differences including arrays, globs, and prompts.
Command
 A mechanism that supplements Unix permissions by granting individual access rights to specific users or groups; use setfacl to configure and getfacl to inspect.
Command
 A widely used open-source web server that organizes configuration per module and virtual host, with optional per-directory overrides via .htaccess.
Command
 A Mandatory Access Control framework built into Ubuntu and Debian. Profiles restrict each process's access to files, network resources, and system calls.
Command
 The standard package management tool for Debian and Ubuntu. Use update to refresh the package list, then install, upgrade, and remove to manage software.
Command
 A daemon that works with the Linux kernel audit subsystem to log file access, command execution, and user operations. Use auditctl to configure rules and ausearch or aureport to analyze the collected data.
Command
 Commands for changing file permissions, owning user, and owning group. Essential for correctly configuring permissions when deploying web applications.
Command
 System cron directories such as /etc/cron.d and /etc/cron.daily, plus anacron which runs missed jobs after the system powers back on.
Command
 Steps for deploying Django to production: isolate the environment with virtualenv, register Gunicorn as a systemd WSGI server, and place Nginx in front as a reverse proxy.
Command
 Production deployment for .NET apps: publish with dotnet publish, register Kestrel as a systemd service, and place Nginx in front as a reverse proxy.
Command
 Deploy Node.js/Express to production using PM2 as a process manager for daemonization and auto-restart, with Nginx in front as a reverse proxy.
Command
 Go compiles to a single binary requiring no runtime installation. Transfer the binary to the server, register it as a systemd service, and configure Nginx as a reverse proxy.
Command
 A step-by-step guide to deploying PHP on Ubuntu: install PHP-FPM, configure an Nginx virtual host, and set correct file permissions.
Command
 Rails production deployment using rbenv for Ruby, Bundler for gems, Puma as a systemd service, and Nginx as a reverse proxy over a Unix socket.
Command
 Use df to check free space across filesystems and du to identify disk usage per directory. Also covers ncdu for interactive drill-down investigation.
Command
 fdisk for interactive MBR/GPT partition management and parted for scriptable non-interactive partition operations on large disks.
Command
 A comparison of Debian-based (Ubuntu, etc.) and RHEL-based (AlmaLinux, etc.) distributions, covering package management, release cycles, and support periods.
Command
 The standard package manager for RHEL and AlmaLinux. Manage packages with install, update, and remove, and supports EPEL repositories and package group installs.
Command
 How Linux resolves hostnames to IP addresses; lookup order is controlled by /etc/nsswitch.conf, and DNS servers are configured via /etc/resolv.conf or systemd-resolved.
Command
 A security tool that automatically detects brute-force attacks and blocks offending IPs via iptables when failed attempts exceed a threshold. Configured per-service in "jail" units.
Command
 The Linux directory layout defined by the Filesystem Hierarchy Standard (FHS), covering the roles of /etc, /var, /usr, /home, /tmp, /proc, and more.
Command
 A family of commands that format partitions to create filesystems. Covers the differences and use cases for ext4, XFS, and Btrfs.
Command
 The standard firewall daemon for RHEL and AlmaLinux. Organizes rules by zone and service, and lets you dynamically open ports and persist changes via firewall-cmd.
Command
 Commands for creating and deleting Linux groups and managing group membership. Group information is stored in /etc/group.
Command
 A command-line tool for controlling Netfilter in the Linux kernel. Add rules to the INPUT, OUTPUT, and FORWARD chains to allow or deny network traffic.
Command
 A command for viewing systemd journal logs. Use -u to filter by service, -p to set error level, and --since/--until to narrow by time range.
Command
 Update the Linux kernel with apt upgrade on Ubuntu or dnf update kernel on RHEL/AlmaLinux. Use needs-restarting to decide if a reboot is needed and auto-remove old kernels.
Command
 A system for automatically obtaining and renewing free SSL/TLS certificates. Run certbot --nginx or --apache to handle certificate issuance and web server configuration automatically.
Command
 Core Linux concepts including the kernel/user-space separation, process management, daemons, and the role of the shell.
Command
 A tool that automatically rotates, compresses, and deletes log files. Place config files in /etc/logrotate.d/ and set rotation triggers with daily, weekly, or size directives.
Command
 A Linux disk abstraction layer with three tiers — Physical Volumes (PV), Volume Groups (VG), and Logical Volumes (LV) — enabling live expansion and snapshot backups.
Command
 ss (iproute2) for fast socket status display and the legacy netstat (net-tools). Use ss -tlnp to list all listening ports.
Command
 The ip command for checking, adding, and removing IP addresses and routes, alongside nmcli for persistent NetworkManager configuration.
Command
 Nginx as a high-performance web server and reverse proxy. Configuration follows the http → server → location hierarchy for virtual hosts, PHP-FPM integration, and reverse proxying.
Command
 Key Nginx performance settings: worker_processes for CPU core alignment, keepalive_timeout for connection reuse, sendfile for static files, and gzip for compression.
Command
 A setup where Nginx serves static files and delegates PHP processing to PHP-FPM via fastcgi_pass, offering better performance and scalability than Apache + mod_php.
Command
 Forwards client requests to a backend application server (Node.js, Django, Rails, etc.) using proxy_pass. Also handles HTTPS termination and load balancing.
Command
 The standard package manager for Arch Linux and derivatives like Manjaro. Use -Syu to update, -S to install, and yay for AUR packages outside the official repositories.
Command
 Two Linux files managing user information: /etc/passwd stores basic user data (world-readable), while /etc/shadow holds password hashes with strict permissions.
Command
 Low-level package tools that operate beneath dnf and apt. Directly install, remove, query, and verify .rpm and .deb package files.
Command
 A command that incrementally synchronizes files between local and remote locations. Transfers only changed files for speed and bandwidth efficiency; widely used with SSH for secure backups.
Command
 A Linux system log collection daemon. Routes log output based on facility and severity combinations, and supports forwarding to remote servers with the @@ notation.
Command
 The sar command from the sysstat package collects and stores CPU, memory, I/O, and network statistics over time, allowing historical analysis of past performance issues.
Command
 A mandatory access control (MAC) framework built into the Linux kernel. Attaches security labels (contexts) to all resources and enforces a policy that allows only explicitly permitted operations. Standard on RHEL and AlmaLinux.
Command
 Initial security steps for a new server: disable unnecessary services, switch to SSH key auth, enable a firewall, and configure automatic security updates to minimize attack surface.
Command
 Three special permissions beyond rwx: setuid runs a file with the owner's privileges, setgid inherits the directory's group, and sticky bit prevents users from deleting others' files in shared directories.
Command
 Register your client-generated public key in ~/.ssh/authorized_keys on the server for passwordless login. The .ssh/ directory requires 700 and authorized_keys requires 600 permissions.
Command
 An SSH client config file where you specify HostName, User, Port, and IdentityFile per host, allowing shorter alias names instead of long command-line options.
Command
 A command for generating SSH key pairs. Register the public key on the server and keep the private key locally. ED25519 is recommended for new keys due to its security and speed.
Command
 A mechanism to forward arbitrary TCP ports through an encrypted SSH connection. Local (-L), remote (-R), and dynamic (-D) forwarding enable secure database access, internal service exposure, and more.
Command
 The SSH server config file at /etc/ssh/sshd_config. Always set PasswordAuthentication no and PermitRootLogin no as baseline security hardening.
Command
 Nginx SSL config combines certificate paths, TLS version selection, cipher suites, and HSTS headers. Disable TLS 1.0/1.1 and allow only 1.2/1.3 to achieve an A+ rating on SSL Labs.
Command
 A protocol for encrypting internet communication. SSL is the old name; TLS is what is actually used today. Hybrid encryption prevents eavesdropping, tampering, and impersonation, with CAs verifying server identity.
Command
 sudo delegates root-level operations to regular users; visudo safely edits the /etc/sudoers configuration file with syntax checking.
Command
 systemd targets replace SysVinit runlevels. Covers multi-user.target (runlevel 3), graphical.target (runlevel 5), and how to switch or set the default target.
Command
 Schedule periodic tasks using .timer unit files paired with .service files. Advantages over cron include centralized logging via journalctl and relative time scheduling.
Command
 Register your own application as a daemon by creating a .service file with [Unit], [Service], and [Install] sections. Then manage start, stop, and auto-start with systemctl.
Command
 top displays real-time CPU, memory, and load average; htop extends it with color, mouse support, and tree view for more intuitive process inspection and signal sending.
Command
 A simplified firewall management tool built into Ubuntu that wraps iptables. Use intuitive commands like ufw allow, deny, and status to manage packet filtering rules.
Command
 Three commands for managing Linux users: useradd creates a user with home directory, shell, and group; usermod modifies settings; userdel -r deletes the user along with their home directory.
Command
 The standard Linux directory for logs including kernel messages, authentication records, and service access logs. Monitor in real time with tail -f, search with grep, and query rotated logs with zcat/zgrep.
Command
 vmstat outputs real-time memory, swap, CPU, and I/O statistics; iostat shows per-disk I/O throughput and latency. Both are lightweight tools for quickly identifying performance bottlenecks.
C#
 An overview of C#, the .NET platform, Unity, and how execution works (.cs → csc → IL → CLR), with a recommended learning order for this dictionary.
C#
 Setup instructions for installing and running C#.
C#
 How to write and run .cs files.
C#
 Gets the length of a string and searches for a character position.
C#
 Extracts and removes parts of a string.
C#
 Replaces parts of a string and checks for containment.
C#
 Converts case and removes whitespace.
C#
 Splits and joins strings.
C#
 Pads and formats strings.
C#
 Converts a string to a numeric value.
C#
 Type conversion utilities.
C#
 Checks whether a string is null or empty.
C#
 Gets the length of an array and resizes it.
C#
 Sorts and reverses an array.
C#
 Searches and copies an array.
C#
 Adds, removes, and clears elements in a list.
C#
 Inserts elements into a list and gets the element count.
C#
 Searches and checks for elements within a list.
C#
 Sorts, reverses, and loops through a list.
C#
 Adds and removes keys and values from a dictionary.
C#
 Safely retrieves values and checks for key existence in a dictionary.
C#
 Retrieves keys and values from a dictionary and loops through them.
C#
 Absolute value, rounding, ceiling, and floor operations.
C#
 Maximum, minimum, power, and square root operations.
C#
 Constants and random number generation.
C#
 Filters elements that match a condition.
C#
 Transforms each element to generate a new sequence.
C#
 Sorts a sequence.
C#
 Groups elements in a sequence.
C#
 Joins two sequences.
C#
 Retrieves the first, last, or single element.
C#
 Aggregates count, sum, and average.
C#
 Evaluates conditions on sequence elements.
C#
 Removes duplicates, limits count, and skips elements.
C#
 Converts LINQ query results to a collection.
C#
 Performs cumulative operations.
C#
 Generates sequences.
C#
 Defines and awaits asynchronous methods.
C#
 Runs tasks and introduces delays.
C#
 Creates immediately completed tasks and handles cancellation.
C#
 Handles exceptions inside asynchronous methods.
C#
 Reads and writes an entire text file at once.
C#
 Checks existence, deletes, and copies files.
C#
 Reads and writes files line by line using streams.
C#
 Creates and checks directories.
C#
 Manipulates path strings.
C#
 Catches exceptions and performs cleanup.
C#
 Throws exceptions and defines custom exception types.
C#
 Outputs to the console.
C#
 Reads input from the console.
C#
 Gets the current date and time.
C#
 Converts a string to a DateTime value.
C#
 Formats a DateTime and adds or subtracts time.
C#
 Calculates and represents a time interval.
C#
 A collection that contains no duplicate elements.
C#
 Queue and stack data structures.
C#
 Base interfaces for collections.
C#
 Sets a default value for null and assigns it.
C#
 Type checking and conversion.
C#
 Allows value types to hold null.
C#
 Outputs debug information to the console.
C#
 Finds objects and retrieves components in Unity.
C#
 A set of math functions specific to Unity.
C#
 Calculations for 2D and 3D coordinate vectors.
C#
 Splits processing over time using coroutines.
C#
 An overview of C# basic data types, covering value/reference types, var type inference, and implicit/explicit conversions.
C#
 How to write single-line (//), block (/* */), and XML documentation (///) comments in C#.
C#
 The basic syntax of the for loop with initialization, condition, and update expressions, plus break and continue.
C#
 The foreach statement for iterating over arrays and IEnumerable collections without an index variable.
C#
 The basic conditional branching syntax; C# requires a bool expression in every condition.
C#
 The Main method as the program entry point, and how the static modifier shares members across instances.
C#
 Overview of arithmetic, comparison, and logical operators, including integer division behavior and Nullable types.
C#
 Type, constant, and property patterns with is, switch expressions, and when guard clauses in C#.
C#
 Immutable data types added in C# 9, supporting with expressions, value equality, and Deconstruct.
C#
 How return exits a method and returns a value, plus early return, guard clauses, and multi-value returns with tuples.
C#
 The $"..." syntax for embedding variables and expressions in strings with {} placeholders and format specifiers.
C#
 Multi-branch switch statement and the switch expression introduced in C# 8, supporting strings, enums, and type patterns.
C#
 The ternary operator ?: , null-conditional ?. for safe member access, and ?? / ??= for null fallback values.
C#
 Two uses of using: importing namespaces and automatically disposing IDisposable objects.
C#
 How var lets the compiler infer the type from the right-hand side, along with where it can and cannot be used.
C#
 The while loop that runs while a condition is true, and do-while that always executes at least once.
CSS
 An overview of CSS, how cascading, specificity, and inheritance work, and a recommended learning order for this dictionary.
CSS
 Comment syntax in /* */, when to write comments, and when not to.
CSS
 Step-by-step guide to setting up an environment for writing and displaying CSS.
CSS
 How to write .css files and display them in a browser.
CSS
 Specifies how rows are aligned along the cross axis of a flex container.
CSS
 Specifies how flex items are aligned along the cross axis.
CSS
 Specifies the cross-axis alignment for an individual flex item.
CSS
 Shorthand property for specifying all animation-related settings at once.
CSS
 Specifies the delay before an animation starts.
CSS
 Specifies the duration of one animation cycle.
CSS
 Specifies whether the animation should alternate direction on each cycle.
CSS
 Specifies the state of an element before and after the animation plays.
CSS
 Specifies the number of times an animation repeats.
CSS
 Specifies the name of the animation.
CSS
 Specifies the timing and rate of change for an animation.
CSS
 Shorthand property for specifying all background-related settings at once.
CSS
 Specifies whether the background scrolls with the page or stays fixed.
CSS
 Specifies the area in which the background is displayed.
CSS
 Specifies the background color.
CSS
 Specifies the background image.
CSS
 Specifies the origin position (reference point) for background rendering.
CSS
 Specifies the starting position for rendering the background image.
CSS
 Specifies how the background image is repeated.
CSS
 Specifies the size of the background image.
CSS
 Shorthand property for specifying border settings on all four sides.
CSS
 Shorthand property for specifying bottom border settings.
CSS
 Specifies the color of the bottom border.
CSS
 Specifies the radius of the bottom-left corner.
CSS
 Specifies the radius of the bottom-right corner.
CSS
 Specifies the style of the bottom border.
CSS
 Specifies the width of the bottom border.
CSS
 Specifies whether table cell borders are shared or separated.
CSS
 Shorthand property for specifying border colors on all four sides.
CSS
 Shorthand property for specifying left border settings.
CSS
 Specifies the color of the left border.
CSS
 Specifies the style of the left border.
CSS
 Specifies the width of the left border.
CSS
 Shorthand property for specifying border-radius on all four corners.
CSS
 Shorthand property for specifying right border settings.
CSS
 Specifies the color of the right border.
CSS
 Specifies the style of the right border.
CSS
 Specifies the width of the right border.
CSS
 Specifies the spacing between table cell borders.
CSS
 Shorthand property for specifying border styles on all four sides.
CSS
 Shorthand property for specifying top border settings.
CSS
 Specifies the color of the top border.
CSS
 Specifies the radius of the top-left corner.
CSS
 Specifies the radius of the top-right corner.
CSS
 Specifies the style of the top border.
CSS
 Specifies the width of the top border.
CSS
 Shorthand property for specifying border widths on all four sides.
CSS
 Specifies the distance from the bottom edge of the reference position.
CSS
 Specifies the direction in which child elements are laid out inside a box.
CSS
 Specifies the shadow of the content box.
CSS
 Changes how the box model (element size) is calculated.
CSS
 A CSS function that performs arithmetic calculations.
CSS
 Cancels the wrap-around caused by a preceding floated element.
CSS
 Specifies whether an element is clipped.
CSS
 Specifies the column spacing between flex or grid items.
CSS
 Specifies the text color (font color).
CSS
 Inserts content into :before and :after pseudo-elements.
CSS
 Changes the design of the mouse cursor.
CSS
 Specifies the direction of text flow.
CSS
 Specifies the display type of an element.
CSS
 Specifies how to display empty table cell elements.
CSS
 Applies filter effects to images or text.
CSS
 Shorthand property for specifying flex item growth and shrink settings.
CSS
 Specifies the initial size of a flex item.
CSS
 Specifies the direction of the main axis in a flex container.
CSS
 Shorthand property for flex-direction and flex-wrap.
CSS
 Specifies the growth factor of a flex item.
CSS
 Specifies the shrink factor of a flex item.
CSS
 Specifies whether flex items wrap onto multiple lines.
CSS
 Makes an element float and positions it to the left or right.
CSS
 Shorthand property for specifying all font-related settings.
CSS
 Specifies the font family.
CSS
 Specifies the font size.
CSS
 Specifies the font style.
CSS
 Specifies small-caps display settings for the font.
CSS
 Specifies the weight (boldness) of the font.
CSS
 Shorthand property for specifying spacing between flex or grid items.
CSS
 Specifies the height of an element.
CSS
 Specifies how flex items are aligned along the main axis.
CSS
 Specifies the distance from the left edge of the reference position.
CSS
 Specifies the spacing between characters.
CSS
 Applies a linear gradient to the background color.
CSS
 Specifies the minimum height of a line box.
CSS
 Shorthand property for specifying list marker settings.
CSS
 Specifies the image to use as a list marker.
CSS
 Specifies the position of the list marker.
CSS
 Specifies the type of list marker.
CSS
 Shorthand property for specifying margins on all four sides.
CSS
 Specifies the bottom margin.
CSS
 Specifies the left margin.
CSS
 Specifies the right margin.
CSS
 Specifies the top margin.
CSS
 Specifies the maximum height of an element.
CSS
 Specifies the maximum width of an element.
CSS
 Specifies the minimum height of an element.
CSS
 Specifies the minimum width of an element.
CSS
 Specifies the opacity of an element.
CSS
 Specifies the display order of flex items.
CSS
 Shorthand property for specifying all outline-related settings.
CSS
 Specifies the color of the outline.
CSS
 Specifies the style of the outline.
CSS
 Specifies the width of the outline.
CSS
 Specifies how overflowing content is displayed.
CSS
 Specifies how overflowing content is displayed in the horizontal (x-axis) direction.
CSS
 Specifies how overflowing content is displayed in the vertical (y-axis) direction.
CSS
 Shorthand property for specifying padding on all four sides.
CSS
 Specifies the bottom padding.
CSS
 Specifies the left padding.
CSS
 Specifies the right padding.
CSS
 Specifies the top padding.
CSS
 Specifies page break positions after an element when printing.
CSS
 Specifies page break positions before an element when printing.
CSS
 Specifies how an element is positioned.
CSS
 Applies a radial gradient to the background color.
CSS
 Specifies the distance from the right edge of the reference position.
CSS
 Specifies the row spacing between flex or grid items.
CSS
 How selector specificity is calculated to determine style priority.
CSS
 Specifies how cell widths in a table element are determined.
CSS
 Specifies the horizontal alignment of inline content.
CSS
 Specifies text decoration.
CSS
 Specifies the indentation width of the first line of text.
CSS
 Truncates overflowing text and displays an ellipsis at the end.
CSS
 Specifies a shadow for text.
CSS
 Specifies the capitalization of text such as English letters.
CSS
 Specifies the distance from the top edge of the reference position.
CSS
 Applies 2D or 3D transformation effects.
CSS
 Specifies the origin point for 2D or 3D transformations.
CSS
 Shorthand property for specifying all transition effect settings at once.
CSS
 Specifies when the transition effect begins.
CSS
 Specifies the duration of the transition effect.
CSS
 Specifies the CSS property name to apply the transition effect to.
CSS
 Specifies the timing and easing of the transition effect.
CSS
 Overrides the Unicode text direction.
CSS
 Specifies the vertical alignment position.
CSS
 Defines and references CSS variables (custom properties).
CSS
 Specifies whether an element is visible or hidden.
CSS
 Specifies how spaces, tabs, and line breaks are displayed.
CSS
 Specifies the width of an element.
CSS
 Specifies the spacing between words.
CSS
 Specifies whether line breaks can occur in the middle of a word.
CSS
 Specifies the stacking level (z-order) of an element.
CSS
 A comprehensive summary of CSS grammar.
CSS
 Names of each part of CSS selectors and HTML elements.
CSS
 Applies to all elements.
CSS
 Applies only while the element is being clicked with the mouse.
CSS
 Generates the last child element of an element.
CSS
 Generates the first child element of an element.
CSS
 Applies to elements that are checked.
CSS
 Targets elements with a specific class name.
CSS
 Applies to elements in a disabled state.
CSS
 Applies to elements in an enabled state.
CSS
 Targets the first child element.
CSS
 Applies to the first character of the first line of an element.
CSS
 Applies to the first line of an element.
CSS
 Targets the first child element of its type.
CSS
 Applies to the element that currently has focus.
CSS
 Applies only while the element is being hovered over with the mouse.
CSS
 Targets elements with a specific ID name.
CSS
 Targets the last child element.
CSS
 Targets the last child element with the same element name.
CSS
 Applies to elements that have a valid link destination.
CSS
 Targets E elements that do not match the selector specified by s.
CSS
 Applies to the nth child element counted from the top.
CSS
 Applies to the nth child element counted from the bottom.
CSS
 Applies to the nth child element with the same element name counted from the top.
CSS
 Applies to the nth child element with the same element name counted from the bottom.
CSS
 Targets the sole child element.
CSS
 Targets the root element of the HTML document.
CSS
 Applies to elements whose ID matches the hash value in the URL.
CSS
 Applies to elements whose link destination has been visited.
CSS
 Applies by specifying the element name.
CSS
 Targets F elements that are descendants of E elements.
CSS
 Targets F elements that are direct children of E elements.
CSS
 Targets F elements immediately adjacent to E elements.
CSS
 Targets F elements at the same level that follow E elements.
CSS
 Targets E elements that have the foo attribute.
CSS
 Applies to elements where the specified attribute and value match exactly.
CSS
 Applies to elements where a word in the specified attribute value matches when split by a space.
CSS
 Applies to elements where the first word of the specified attribute value matches when split by a hyphen.
CSS
 Applies to elements where the specified attribute value starts with the given string.
CSS
 Applies to elements where the specified attribute value ends with the given string.
CSS
 Applies to elements where the specified attribute value contains the given string.
Docker
 A guide to learning order and an overview of containers and images.
Docker
 Comment syntax in #, when to write comments, and when not to.
Docker
 Installing Docker Desktop and verifying it works correctly.
Docker
 Verifying container startup using official images.
Docker
 Core concepts of containers and images, differences from VMs, and Docker architecture.
Docker
 Starting a container with port mapping, volumes, and environment variables.
Docker
 Listing running and stopped containers.
Docker
 Stopping and removing containers.
Docker
 Listing, removing, and tagging local images.
Docker
 Pulling images from and pushing images to a registry.
Docker
 Running commands in a running container.
Docker
 Viewing and following container logs.
Docker
 Inspecting container details and viewing real-time statistics.
Docker
 Building an image from a Dockerfile.
Docker
 Removing unused Docker resources in bulk.
Docker
 Basic structure of a Dockerfile and overview of key instructions.
Docker
 Selecting a base image from options like alpine, slim, and distroless.
Docker
 Executing shell commands during image build.
Docker
 Copying files from host to container.
Docker
 Setting working directory, environment variables, and build arguments.
Docker
 Specifying startup commands and their differences.
Docker
 Declaring ports and defining mount points.
Docker
 Running containers as a non-root user for security.
Docker
 Reducing image size by separating build and runtime stages.
Docker
 Designing layer order to minimize cache invalidation.
Docker
 Multi-architecture builds using BuildKit.
Docker
 Named volumes, bind mounts, and tmpfs.
Docker
 Using named volumes for data persistence.
Docker
 Mounting host directories into containers for development.
Docker
 Docker network types: bridge, host, none, and overlay.
Docker
 Custom bridge networks for container-to-container communication.
Docker
 Host network sharing and complete network isolation.
Docker
 Defining and managing multiple containers with compose.yml.
Docker
 Configuring services with image, ports, volumes, and environment settings.
Docker
 Core commands: up, down, ps, logs, exec, and build.
Docker
 Managing environment variables with .env files and environment properties.
Docker
 Defining named volumes and bind mounts in a compose file.
Docker
 Defining custom networks and DNS resolution between services.
Docker
 Controlling service startup order with health check integration.
Docker
 Using override files to separate development and production settings.
Docker
 Three-container setup with Nginx, PHP-FPM, and MySQL.
Docker
 Express app with Redis session store.
Docker
 Django application with PostgreSQL database.
Docker
 Ruby on Rails with MySQL database.
Docker
 Automating HTTPS with certbot container.
Docker
 Managing public and private repositories and using Official Images.
Docker
 Tagging and pushing images to Docker Hub.
Docker
 Setting up a private registry with the official Docker registry image.
Docker
 Logging in to ECR and pushing or pulling images.
Docker
 Automating image builds and registry pushes with GitHub Actions.
Docker
 Configuring health check commands and monitoring container status.
Docker
 Hardening containers with read-only filesystem, capability dropping, and privilege restriction.
Docker
 Scanning images for CVEs using docker scout.
Docker
 Pinning image tags, health checks, and log management for production.
Docker
 Cluster management with Docker built-in orchestration.
Docker
 Comparing Docker and Kubernetes roles and when to use each.
Go
 An overview of Go covering its features, how execution works, and a recommended learning path through the dictionary pages.
Go
 Comment syntax in // / /* */, when to write comments, and when not to.
Go
 Steps to set up an environment for installing and running Go.
Go
 How to write and run .go files.
Go
 When to use var versus := declarations.
Go
 Integers, floating-point numbers, strings, and booleans.
Go
 Defining constants and auto-generating sequential values.
Go
 Differences between fixed-length arrays and variable-length slices.
Go
 An associative array managed as key-value pairs.
Go
 A mechanism for directly manipulating memory addresses.
Go
 Converting a value to a different type.
Go
 The initial value automatically set at declaration time.
Go
 Basics of conditional branching.
Go
 The only loop syntax in Go.
Go
 Multi-way branching and type switches.
Go
 A mechanism for deferring execution until a function ends.
Go
 Label jumps and loop labels.
Go
 Basics of Go functions and returning multiple values.
Go
 A function that accepts a variable number of arguments.
Go
 Treating functions as values and capturing outer variables.
Go
 Special functions for initialization and the execution entry point.
Go
 Raising and recovering from runtime errors.
Go
 A data structure that groups multiple fields together.
Go
 Defining functions associated with a type.
Go
 A type that defines behavior.
Go
 Defining a new type based on an existing type.
Go
 Writing generic code using type parameters.
Go
 Standard error handling patterns in Go.
Go
 Wrapping errors and chaining causes.
Go
 Creating custom errors by implementing the Error() method.
Go
 Achieving concurrent processing with lightweight threads.
Go
 A mechanism for passing data between goroutines.
Go
 Waiting on multiple channels simultaneously.
Go
 A mechanism for waiting for goroutines to complete.
Go
 Exclusive access to shared resources.
Go
 Writing to standard output.
Go
 String formatting and writing to a writer.
Go
 Reading from standard input.
Go
 A list of format verbs such as %v, %T, and %d.
Go
 Searching and checking strings.
Go
 Splitting, joining, and replacing strings.
Go
 Converting case and trimming strings.
Go
 Converting between strings and numbers.
Go
 Opening, creating, and deleting files.
Go
 Reading and writing files all at once.
Go
 Getting command-line arguments and environment variables.
Go
 I/O interfaces and buffering.
Go
 Sending requests with an HTTP client.
Go
 Starting an HTTP server.
Go
 Manipulating requests and responses.
Go
 URL routing mechanism.
Go
 Converting between Go and JSON.
Go
 Reading and writing JSON as a stream.
Go
 JSON field names and options for struct fields.
Go
 Getting the time, sleeping, and formatting.
Go
 Basic mathematical functions.
Go
 Generating random numbers.
Go
 Sorting slices.
Go
 Pattern matching with regular expressions.
Go
 Defining and importing packages.
Go
 Dependency management tool.
Go
 Commonly used Go commands.
HTML
 An overview of HTML, features and trade-offs, the role of major tags, and a recommended learning order for this dictionary.
HTML
 Comment syntax in <!-- -->, when to write comments, and when not to.
HTML
 Steps for setting up an environment to write and display HTML.
HTML
 How to write .html files and display them in a browser.
HTML
 Document type declaration and the root HTML element.
HTML
 Container for document metadata.
HTML
 Configuring metadata.
HTML
 Linking external resources.
HTML
 Container for the document body.
HTML
 Identifying and grouping elements.
HTML
 Inline styles, tooltips, and language settings.
HTML
 Custom data attributes, visibility, and focus order.
HTML
 Heading tags.
HTML
 Paragraphs.
HTML
 General-purpose block container.
HTML
 Preformatted text, quotations, and horizontal rules.
HTML
 Unordered and ordered lists.
HTML
 General-purpose inline container.
HTML
 Important and emphasized text.
HTML
 Displaying code, keyboard input, and variables.
HTML
 Line breaks and ruby annotations.
HTML
 Text decoration elements.
HTML
 Hyperlinks.
HTML
 Navigation block.
HTML
 Definition lists (terms and descriptions).
HTML
 Page and section headers and footers.
HTML
 Main content and standalone articles.
HTML
 Sections and supplementary information.
HTML
 Collapsible content.
HTML
 Basic table structure.
HTML
 Table grouping and captions.
HTML
 Merging table cells.
HTML
 Container for forms.
HTML
 Text input fields.
HTML
 Checkboxes and radio buttons.
HTML
 Buttons, file inputs, and hidden fields.
HTML
 Multi-line input and dropdowns.
HTML
 Labels, grouping, and legends.
HTML
 Button elements.
HTML
 Key attributes for form inputs.
HTML
 Input restrictions and validation.
HTML
 Date and time inputs.
HTML
 Number inputs, sliders, and suggestion lists.
HTML
 Embedding images.
HTML
 Responsive images and media switching.
HTML
 Figures and captions.
HTML
 Embedding video.
HTML
 Embedding audio.
HTML
 Inline frames for embedding external content.
HTML
 Embedding and loading JavaScript.
HTML
 Canvas drawing and SVG images.
HTML
 Embedding CSS.
HTML
 Fallback content for when scripts are disabled.
HTML
 Explicitly defining the role of an element.
HTML
 Associating names and descriptions with elements.
HTML
 Visibility state and notifications of dynamic updates.
HTML
 Metadata for search engines and social media.
HTML
 Canonical URLs and multi-language support.
HTML
 Favicons and resource preloading.
HTML
 Dialog boxes.
HTML
 Templates and Web Components slots.
Java
 An overview of Java, Write Once Run Anywhere, static typing, how execution works (.java → javac → .class → JVM), and a recommended learning path through this dictionary.
Java
 Comment syntax in // / /* */ / /** */, when to write comments, and when not to.
Java
 Setup instructions for installing, compiling, and running Java.
Java
 How to write, compile, and run .java files.
Java
 Gets the length of a string and retrieves a character at a specific position.
Java
 Searches for a substring and checks its existence.
Java
 Checks prefix, suffix, and regular expression matching.
Java
 Extracts a portion of a string.
Java
 Replaces parts of a string.
Java
 Converts case and removes whitespace.
Java
 Splits and joins strings.
Java
 Compares strings.
Java
 Converts between numbers and strings.
Java
 Converts between a string and a character array.
Java
 Mutable string operations for appending and inserting.
Java
 Reverses, replaces, and converts strings.
Java
 Sorts an array and performs binary search.
Java
 Copies and fills arrays.
Java
 Compares arrays, converts to string, and converts to List.
Java
 Creates a list, and adds, updates, and retrieves elements.
Java
 Removes elements, clears a list, and checks its size.
Java
 Searches within a list and retrieves a sublist.
Java
 Sorts, shuffles, and reverses a list.
Java
 Creates a map, and adds and retrieves entries.
Java
 Removes entries and checks for key existence.
Java
 Retrieves keys, values, and entries from a map.
Java
 Creates a set, and adds, checks, and removes elements.
Java
 Gets the size of a set and iterates over it.
Java
 Operations on a queue.
Java
 Operations on a stack and double-ended queue.
Java
 Creates a stream and filters or transforms its elements.
Java
 Collects a stream into a collection.
Java
 Iterates over, aggregates, and counts stream elements.
Java
 Sorts, removes duplicates, and limits stream elements.
Java
 Searches and evaluates conditions on stream elements.
Java
 A null-safe wrapper class.
Java
 Converts a string to a numeric value.
Java
 Integer constants and radix conversion.
Java
 Performs numerical calculations and rounding.
Java
 Gets or creates a date.
Java
 Gets the current date, time, or datetime.
Java
 Formats and parses date and time values.
Java
 Reads from standard input, strings, and numbers.
Java
 Reads input with buffering.
Java
 Reads the entire content of a file.
Java
 Writes content to a file.
Java
 Checks and creates files and directories.
Java
 Copies, moves, and lists files.
Java
 Compiles a regular expression and performs matching.
Java
 Replaces text using a regular expression.
Java
 The basic syntax for exception handling.
Java
 Automatically closes resources.
Java
 Defines a class and creates an instance.
Java
 Access modifiers, static members, and constants.
Java
 Inheritance and method overriding.
Java
 Interfaces and abstract classes.
Java
 The Objects utility class.
Java
 Defines classes and methods with type parameters.
Java
 A concise syntax for anonymous functions.
Java
 Major functional interfaces.
Java
 Defines and uses enumeration types.
Java
 An immutable data class.
Java
 Creates and starts a thread.
Java
 Executes tasks using a thread pool.
Java
 Asynchronous processing.
Java
 Standard output, error output, and standard input.
Java
 Time measurement and process termination.
Java
 Checks the type of an object and converts it to a string.
Java
 Fixed-length arrays in Java; covers declaration, initialization, element access, multi-dimensional arrays, and when to use ArrayList instead.
Java
 The final keyword makes variables non-reassignable, methods non-overridable, and classes non-inheritable in Java.
Java
 The for loop combining initialization, condition, and update; covers counting, break, continue, and labeled nested loops.
Java
 The enhanced for statement that iterates over arrays and Iterable collections concisely without an index variable.
Java
 The basic conditional branching syntax in Java.
Java
 The import statement for using classes and interfaces; covers individual, wildcard, and static imports.
Java
 The public static void main(String[] args) entry point and how static methods and fields work in Java.
Java
 Arithmetic, comparison, and logical operators; covers integer division truncation, the + operator for strings, and short-circuit evaluation.
Java
 The eight primitive types that store values directly on the stack; covers bit size, value range, wrapper classes, and type conversion.
Java
 Declaring return types, returning values with return, early exit in void methods, and returning multiple values.
Java
 The switch statement and the switch expression finalized in Java 14; covers strings, enums, and returning values with yield.
Java
 Writes if/else as a one-liner with condition ? true_value : false_value; covers type constraints and readability of nesting.
Java
 var added in Java 10 lets the compiler infer the local variable type from the right-hand side; not usable for fields, parameters, or return types.
Java
 The while loop that repeats while true and do-while that always runs once first; covers infinite loops and input-loop patterns.
JavaScript
 An overview of JavaScript and a guide to the recommended learning order for each feature.
JavaScript
 Step-by-step guide to setting up an environment for running JavaScript.
JavaScript
 How to write .js files and run them with Node.js or in a browser.
JavaScript
 Gets the first HTML element matching the given CSS selector.
JavaScript
 Gets all HTML elements matching the given CSS selector.
JavaScript
 Gets the HTML element with the specified ID.
JavaScript
 Gets or sets the text content of an HTML element without interpreting HTML tags.
JavaScript
 Gets or sets the inner HTML of an element as a string.
JavaScript
 Adds, removes, toggles, or checks for classes on an HTML element.
JavaScript
 Gets the value of the specified attribute of an HTML element.
JavaScript
 Sets the specified attribute on an HTML element.
JavaScript
 Creates a new HTML element with the specified tag name.
JavaScript
 Appends an HTML element as the last child of a parent element.
JavaScript
 Registers an event listener on an HTML element.
JavaScript
 Removes an HTML element; remove() removes itself, removeChild() removes a child element.
JavaScript
 Replaces or inserts a child element; replaceChild() replaces and insertBefore() inserts at a specific position.
JavaScript
 Clones an HTML element; the argument specifies whether to include child elements.
JavaScript
 Searches or tests HTML elements by selector; closest() searches ancestors, matches() checks if the element itself matches.
JavaScript
 Manipulates inline styles; gets, sets, or removes CSS properties.
JavaScript
 Reads and writes data attributes; accesses data-* attributes using camelCase.
JavaScript
 Gets or sets the displayed text content, with a comparison to textContent.
JavaScript
 Creates a text node or document fragment, also useful for XSS prevention.
JavaScript
 Gets the parent element, with a comparison between parentNode and parentElement.
JavaScript
 Gets child elements; children returns all children, first/last returns the first or last.
JavaScript
 Gets sibling elements; retrieves the next or previous HTML element.
JavaScript
 Removes an event listener; note that anonymous functions cannot be removed.
JavaScript
 Gets the event source element; target is the actual element, currentTarget is where the listener is registered.
JavaScript
 Cancels or stops event propagation; suppresses default behavior and controls bubbling.
JavaScript
 Fires a custom event; CustomEvent allows attaching data to the event.
JavaScript
 Adds or removes elements at the end or beginning of an array.
JavaScript
 Adds, removes, or replaces elements at any position in an array.
JavaScript
 Iterates over an array or transforms it; forEach() has no return value, map() returns a new array.
JavaScript
 Search for the first element that matches a condition.
JavaScript
 Extracts all elements matching a condition into a new array.
JavaScript
 Reduces an array to a single value; useful for sums, maximums, and object conversions.
JavaScript
 Checks for a value in an array or finds its position; includes() returns true/false, indexOf() returns the position.
JavaScript
 Tests conditions across an array; some() is true if any match, every() is true if all match.
JavaScript
 Extracts a portion of an array or concatenates arrays without modifying the original.
JavaScript
 Sorts or reverses an array; a comparison function controls the order of numbers or strings.
JavaScript
 Flattens a nested array; flat() expands it, flatMap() performs map and flat simultaneously.
JavaScript
 Converts between arrays and strings; join() joins, split() splits.
JavaScript
 Creates or checks arrays; Array.from() converts array-like objects into arrays.
JavaScript
 Searches within a string or checks for existence; indexOf() returns the position, includes() returns true/false.
JavaScript
 Checks the beginning or end of a string; determines whether it starts or ends with a given string.
JavaScript
 Extracts a portion of a string by specifying start and end positions.
JavaScript
 Gets the character at a specified position; at() also supports negative indexes.
JavaScript
 Replaces text in a string; replace() replaces the first occurrence, replaceAll() replaces all.
JavaScript
 Converts text to uppercase or lowercase; also useful for case-insensitive comparisons.
JavaScript
 Removes whitespace; deletes whitespace from the start, end, or both sides of a string.
JavaScript
 Pads or repeats a string; useful for zero-padding or generating fixed-length strings.
JavaScript
 Gets a list of object keys or values as an array for loop processing.
JavaScript
 Copies or merges objects; also covers comparison with spread syntax.
JavaScript
 Prevents changes to an object; freeze() fully freezes it, seal() only prevents adding or deleting properties.
JavaScript
 Converts a string to a number; parseInt() converts to an integer, parseFloat() to a decimal.
JavaScript
 Checks whether a value is a number, NaN, a finite number, or an integer safely.
JavaScript
 Formats a number as a string with a specified number of decimal places or significant digits.
JavaScript
 Rounds a number; floor rounds down, ceil rounds up, round rounds to nearest, trunc removes decimals.
JavaScript
 Compares numbers, generates random numbers, or gets absolute values; also covers use with arrays.
JavaScript
 Creates a date-time object; gets the current time, a specific date, or a timestamp.
JavaScript
 Gets individual date-time components such as year, month, day, and day of the week.
JavaScript
 Converts date-time to a string; supports locale-aware display and ISO format conversion.
JavaScript
 Converts JSON; converts between strings and objects bidirectionally.
JavaScript
 Basic Promise operations; handles success and failure of asynchronous processing.
JavaScript
 Controls multiple Promises; waits for all to complete, all results, the fastest, or the first success.
JavaScript
 A concise syntax for asynchronous processing; writes Promises more intuitively.
JavaScript
 Executes a process after a specified delay; can be cancelled with clearTimeout().
JavaScript
 Repeats a process at a specified interval; can be stopped with clearInterval().
JavaScript
 Sends HTTP requests using a Promise-based communication API.
JavaScript
 A traditional HTTP request method for environments where fetch() is unavailable.
JavaScript
 Saves data in the browser; localStorage persists permanently, sessionStorage persists per tab.
JavaScript
 Outputs to the console; essential methods for debugging.
JavaScript
 Controls page navigation and history; retrieves URLs and handles page transitions.
JavaScript
 Pattern matching with regular expressions; test() returns true/false, exec() returns detailed results.
JavaScript
 Searches strings with regular expressions; match() finds matches, search() returns the position.
JavaScript
 A collection that manages key-value pairs; any type can be used as a key.
JavaScript
 A collection that manages unique values; duplicate values are automatically removed.
JavaScript
 The basic syntax for error handling; controls error catching, processing, and cleanup.
JavaScript
 A concise function expression syntax introduced in ES2015; it lexically binds this, making it widely used in callbacks.
JavaScript
 A class definition syntax introduced in ES2015; groups constructors, methods, and inheritance in one place.
JavaScript
 Single-line (//) and block (/* */) comment syntax; used to explain code intent or temporarily disable code.
JavaScript
 Syntax introduced in ES2015 for unpacking array and object values into variables; supports defaults, aliases, and nesting.
JavaScript
 A loop syntax that writes initialization, condition, and update in one line, suited for counter-based iteration.
JavaScript
 for...in enumerates object property names; for...of iterates over values from iterables such as arrays.
JavaScript
 Two ways to define functions using the function keyword: declarations and expressions, which differ in hoisting behavior.
JavaScript
 The fundamental conditional branching syntax that switches which block to execute based on whether a condition is true or false.
JavaScript
 ES Modules syntax for sharing code between files; export declares public items, import brings them in.
JavaScript
 The three basic operator categories: arithmetic, comparison, and logical; used for calculations, conditions, and boolean logic.
JavaScript
 Syntax for returning a value from a function to the caller; also covers early return guard clauses and returning multiple values.
JavaScript
 Syntax introduced in ES2015 for expanding array and object elements; used for copying, merging, and spreading as arguments.
JavaScript
 A multi-way branching syntax that matches an expression against multiple case labels and executes the matching block.
JavaScript
 A syntax that embeds variables and expressions directly in backtick-quoted strings; also supports multi-line strings.
JavaScript
 A shorthand conditional expression that returns one of two values on a single line based on a condition.
JavaScript
 A keyword that refers to the current context object; its value changes across five different calling contexts.
JavaScript
 typeof returns the type of a value as a string; instanceof checks whether an object is an instance of a specific class.
JavaScript
 Three variable declaration keywords; they differ in scope, hoisting, and reassignability. const is the modern default.
JavaScript
 while evaluates the condition before each iteration; do-while always runs the block once before evaluating the condition.
Kotlin
 An overview of Kotlin covering its origins at JetBrains, Android official status, null safety, and how execution works (.kt → kotlinc → .class → JVM), with a guide to the recommended learning order.
Kotlin
 Setup instructions for installing and running Kotlin.
Kotlin
 How to write, compile, and run .kt files.
Kotlin
 Declares immutable and mutable variables.
Kotlin
 Types for numbers, characters, and booleans.
Kotlin
 A syntax for embedding variables and expressions inside strings.
Kotlin
 Gets the length of a string and checks if it is empty.
Kotlin
 Extracts a substring.
Kotlin
 Replaces parts of a string and trims whitespace.
Kotlin
 Splits and joins strings.
Kotlin
 Converts a string to a numeric value.
Kotlin
 Conditional branching as an expression with a return value.
Kotlin
 A syntax for multi-branch and type-checking conditions.
Kotlin
 Range operators and loops.
Kotlin
 Declares a function with parameters and a return type.
Kotlin
 Concise function definitions.
Kotlin
 Defines and passes anonymous functions.
Kotlin
 A mechanism that uses functions as arguments or return values.
Kotlin
 Inline expansion of lambda expressions.
Kotlin
 The basics of safely handling null values.
Kotlin
 An operator that specifies a default value when the expression is null.
Kotlin
 An operator that forcibly converts a nullable to a non-null type.
Kotlin
 A way to safely process a value after a null check.
Kotlin
 Automatic casting after a type check.
Kotlin
 Class definition and primary constructor.
Kotlin
 A class specialized for holding data.
Kotlin
 A restricted inheritance hierarchy.
Kotlin
 Defines and uses enumeration types.
Kotlin
 Singletons and static members.
Kotlin
 Inheritance and method overriding.
Kotlin
 Defines and implements interfaces.
Kotlin
 A mechanism to add methods to existing classes.
Kotlin
 Defining property accessors.
Kotlin
 A mechanism for deferred initialization.
Kotlin
 A mechanism to delegate a property to another object.
Kotlin
 Assigning multiple variables simultaneously.
Kotlin
 A scope function used for null checks and transformation chains.
Kotlin
 A scope function used for object setup.
Kotlin
 A scope function used for object configuration and initialization.
Kotlin
 A scope function used for debugging and side-effect insertion.
Kotlin
 Creating a list and basic access.
Kotlin
 Filtering and transforming elements.
Kotlin
 Searching elements and checking conditions.
Kotlin
 Sorting a list.
Kotlin
 Flattening nested lists.
Kotlin
 Folding elements into a single value.
Kotlin
 Grouping and partitioning elements.
Kotlin
 Combining two lists together.
Kotlin
 Iterating over elements.
Kotlin
 Creating and manipulating a map.
Kotlin
 Creating a set and performing set operations.
Kotlin
 Creating a lazily evaluated sequence.
Kotlin
 Retrieving results from a sequence.
Kotlin
 Defining and using type parameters.
Kotlin
 Variance annotations for generics.
Kotlin
 A mechanism to retain type information at runtime.
Kotlin
 Syntax for giving a type an alias.
Kotlin
 Basic syntax for exception handling.
Kotlin
 Checking preconditions and state.
Kotlin
 Redefining operators.
Kotlin
 Annotations for Java interoperability.
Kotlin
 Defining suspendable functions.
Kotlin
 Launching coroutines.
Kotlin
 Retrieving asynchronous results.
Kotlin
 Waiting and setting timeouts.
Kotlin
 Asynchronous data streams.
Kotlin
 Data communication between coroutines.
Kotlin
 Three comment types: single-line, block, and KDoc. Block comments can be nested, and KDoc is used with Dokka to auto-generate API documentation.
Kotlin
 Kotlin has no C-style for loop, so index-based iteration is done with ranges, downTo, step, until, indices, and withIndex.
Kotlin
 Keyword for bringing packages, classes, functions, and properties into scope; supports as for aliasing and .* for wildcard imports.
Kotlin
 Kotlin program entry point defined at the top level without a class; command-line arguments are received as Array<String>.
Kotlin
 == checks structural equality by calling equals(); === checks referential identity. The compiler detects unnecessary comparisons with nullable types.
Kotlin
 Arithmetic, comparison, logical, and range operators plus infix functions; == calls equals() unlike in Java.
Kotlin
 Basic control flow for function return, loop exit, and skip; labels allow breaking from nested loops and returning locally from lambdas.
Kotlin
 A feature where the compiler determines the type from the initial value; type annotations can be omitted for val/var when an initial value is provided.
Kotlin
 Loop constructs that repeat a block while a condition is true; while evaluates the condition first, do-while evaluates it after.
Pascal
 Overview of Pascal's structured programming, type system, and learning path.
Pascal
 Installing Free Pascal and running your first program.
Pascal
 How to write .pas files and compile and run them with the fpc command.
Pascal
 Reading and writing text files with TextFile, AssignFile, Reset/Rewrite, and ReadLn/WriteLn.
Pascal
 Binary-format typed files using file of T for direct record-level read and write.
Pascal
 Untyped files that transfer raw byte sequences with BlockRead and BlockWrite for binary data processing.
Pascal
 Declaring and using arrays with explicit index ranges using the array keyword.
Pascal
 Dynamic arrays whose size can be changed at runtime with SetLength.
Pascal
 Open array parameters declared as array of type to accept arrays of any size.
Pascal
 Boolean type with True/False values and logical operators and, or, not, and xor.
Pascal
 Break exits a loop immediately; Continue skips to the next iteration.
Pascal
 Branching by integer, Char, or enumeration value with CASE OF (strings and reals not supported).
Pascal
 Char type for a single character and String type for sequences of characters.
Pascal
 Object Pascal OOP basics: CLASS declaration, Create constructor, and Free destructor.
Pascal
 Polymorphism through VIRTUAL method declaration and OVERRIDE in derived classes.
Pascal
 Three comment syntaxes: { } and (* *) for block comments, and // for line comments.
Pascal
 const section for unchanging values and var section for mutable variables.
Pascal
 Delphi (commercial) and Free Pascal (open-source), both descending from Turbo Pascal.
Pascal
 User-defined enumerated type grouping values under meaningful names.
Pascal
 Catching exceptions with try...except and guaranteeing cleanup with try...finally.
Pascal
 Pascal FOR loop counting up with TO or down with DOWNTO, always by one.
Pascal
 FORWARD declaration to enable mutual recursion by naming a procedure before its implementation.
Pascal
 Defining a FUNCTION that returns a value, contrasted with a value-less PROCEDURE.
Pascal
 Low-level heap operations with GetMem, FreeMem, Move, and FillChar.
Pascal
 Branching on a condition with the IF~THEN~ELSE syntax.
Pascal
 Multiple integer types differing in size and signedness, such as Integer, Byte, and LongInt.
Pascal
 INTERFACE type in Object Pascal, equivalent to Java's interface with only method signatures.
Pascal
 Implementing a dynamic linked list by combining record types and pointer types.
Pascal
 Built-in math functions including Abs, Sqrt, Round, and Trunc.
Pascal
 Procedures and functions defined inside another procedure or function body.
Pascal
 Dynamically allocating heap memory with New and releasing it with Dispose.
Pascal
 Ord converts to ordinal, Chr creates a character, Succ and Pred move to adjacent values.
Pascal
 Standard output with WriteLn and Write, and standard input with ReadLn and Read.
Pascal
 Three parameter passing modes: value (default), VAR (by reference), and CONST (read-only reference).
Pascal
 Declaring pointer types with ^ and managing heap memory with New and Dispose.
Pascal
 Defining a named block of reusable code that returns no value with PROCEDURE.
Pascal
 Pascal's three-part structure: program declaration, declarations section, and begin...end.
Pascal
 Generating random numbers with Random and seeding from the current time with Randomize.
Pascal
 Choosing between real types like Single, Double, and Extended based on precision and range.
Pascal
 RECORD type grouping fields of different types, equivalent to a C struct.
Pascal
 Accessing record fields without the record variable name prefix using the with statement.
Pascal
 Post-condition loop that evaluates its condition at the end and exits when TRUE.
Pascal
 Pascal's set type for collections of ordinal values, with union, intersection, and difference.
Pascal
 Key Free Pascal standard units including SysUtils, Math, and Classes.
Pascal
 Standard string functions: Length, Copy, Pos, Concat, Delete, and Insert.
Pascal
 Defining a subrange type that restricts the value range of an ordinal type (lower..upper).
Pascal
 Declaring type aliases, enumerations, and subranges in the type section.
Pascal
 UNIT module declaring public symbols in INTERFACE and implementing them in IMPLEMENTATION.
Pascal
 Importing a unit with USES to access all its publicly declared symbols.
Pascal
 Sharing a memory region as multiple types within a RECORD using a case section.
Pascal
 Pre-condition WHILE DO loop that evaluates its condition first and repeats while TRUE.
Perl
 Perl overview, sigils, regex, CPAN, and recommended learning order.
Perl
 Comment syntax in # / =pod...=cut, when to write comments, and when not to.
Perl
 Installing Perl and running your first script.
Perl
 How to write .pl files and run them from the command line.
Perl
 Perl array basics with @sigil, list creation, and element manipulation.
Perl
 Filtering with grep and transforming with map for list processing.
Perl
 Adding and removing elements at both ends of a Perl array.
Perl
 Array slices and element count from scalar context.
Perl
 Lexicographic and numeric sort, reverse, and the Schwartzian transform.
Perl
 Removing, replacing, and inserting array elements at a given position.
Perl
 Web programming basics with CGI.pm for HTTP headers and form parameters.
Perl
 How context changes Perl values and detecting context with wantarray.
Perl
 Installing Perl modules with cpanm and local::lib for local environments.
Perl
 Dates and times with localtime, POSIX::strftime, and the DateTime module.
Perl
 Terminating with die, issuing warnings with warn, and reading $@.
Perl
 Catching exceptions with eval and reading $@, plus Try::Tiny syntax.
Perl
 Exporting functions from a module with @EXPORT and @EXPORT_OK.
Perl
 Recursive file search with File::Find and path parsing with File::Basename.
Perl
 Opening and closing files with three-argument open and or die.
Perl
 Reading lines with <> and iterating all lines with while (<>).
Perl
 File test operators for existence, type, permissions, and size.
Perl
 Writing and appending to files with > and >> mode in open.
Perl
 C-style for loop and foreach list iteration with the $_ default variable.
Perl
 Parsing command-line options and flags with Getopt::Long.
Perl
 Perl's given/when switch and deprecation of smart match.
Perl
 Perl hash basics with %sigil, fat-comma, and key-value access.
Perl
 Testing key presence with exists and removing entries with delete.
Perl
 Retrieving keys, values, and pairs from a hash with keys, values, each.
Perl
 Merging hashes and batch assignment with hash slices.
Perl
 Branching with if, elsif, else, unless, and postfix forms.
Perl
 Converting Perl data to JSON and back with encode_json and decode_json.
Perl
 Sending HTTP requests and reading responses with LWP::UserAgent.
Perl
 OOP in Perl with Moose: attributes, inheritance, and roles.
Perl
 Loop control with next, last, redo, and labeled loops.
Perl
 One-liner scripts with -e, -p, -n, and -i flags as awk/sed alternatives.
Perl
 Setting up inheritance with @ISA or use parent and calling SUPER::.
Perl
 Defining methods as subs in a package with $self as the first argument.
Perl
 Creating objects by blessing a reference into a package namespace.
Perl
 Postfix if, unless, while, until, and for for concise one-line statements.
Perl
 Standard output with print and say, which appends a newline automatically.
Perl
 Formatted output with printf and formatted strings returned by sprintf.
Perl
 Creating references with \ and dereferencing with -> for nested data.
Perl
 Capture groups, non-capturing (?:), named captures, and boundary assertions.
Perl
 Character classes, shorthand \d, \w, \s, and negated variants.
Perl
 Position-only assertions with lookahead (?=) and lookbehind (?<=).
Perl
 Regex matching with the m// operator, =~, and modifier flags.
Perl
 Greedy and non-greedy quantifiers *, +, ?, and {n,m}.
Perl
 Regex substitution with s///, and g, e, r modifier flags.
Perl
 Scalar variables storing numbers, strings, and undef with context rules.
Perl
 Key special variables: $_, $!, $0, $/, and use English aliases.
Perl
 I/O special variables: $/ record separator, $\ output separator, $, and $".
Perl
 Reading standard input with <STDIN> and removing newlines with chomp.
Perl
 Finding substring positions from the start or end with index and rindex.
Perl
 String length with length and substring extraction or replacement with substr.
Perl
 Reversing strings with reverse and repeating them with the x operator.
Perl
 Splitting strings with split and joining lists with join.
Perl
 Case conversion with uc, lc, ucfirst, and lcfirst.
Perl
 Anonymous subs and closures that capture variables from their defining scope.
Perl
 Extracting arguments from @_ and returning multiple values with return.
Perl
 Defining and calling subroutines with sub, @_, and return.
Perl
 Compile-time use vs. runtime require and exporting with Exporter.
Perl
 While loops while true, until loops while false, with post-condition form.
PHP
 An overview of PHP, how execution works, and a recommended learning order for this dictionary.
PHP
 Step-by-step guide to setting up an environment for running PHP.
PHP
 How to write and run .php files.
PHP
 Gets the length of a string.
PHP
 Searches a string and gets the position of a substring.
PHP
 Extracts a portion of a string.
PHP
 Replaces a substring within a string.
PHP
 Converts a string between uppercase and lowercase.
PHP
 Removes whitespace; deletes whitespace from the start, end, or both sides of a string.
PHP
 Converts between strings and arrays bidirectionally.
PHP
 Formats strings and numbers.
PHP
 Pads or repeats a string.
PHP
 Compares two strings.
PHP
 Escapes HTML characters for XSS prevention.
PHP
 Handles line breaks and formats text.
PHP
 Encodes URLs or converts to Base64.
PHP
 Adds or removes elements at the end or beginning of an array.
PHP
 Manipulates or extracts elements at any position in an array.
PHP
 Combines or merges arrays.
PHP
 Gets the keys or values of an array.
PHP
 Removes duplicates, reverses, or extends an array.
PHP
 Searches for a value or key within an array.
PHP
 Gets common elements or differences between arrays.
PHP
 Sorts or reverses an array; a comparison function controls the order of numbers or strings.
PHP
 Sorting arrays with a user-defined comparison function.
PHP
 Transforming and extracting array values.
PHP
 Aggregating arrays and processing each element.
PHP
 Counting array elements, summing, and generating ranges.
PHP
 Converting values to numbers and formatting them.
PHP
 Rounding numeric values.
PHP
 Getting maximum, minimum values, and generating random numbers.
PHP
 Creates a date-time object; gets the current time, a specific date, or a timestamp.
PHP
 Parsing date/time strings.
PHP
 Object-oriented date and time manipulation.
PHP
 Reading and writing entire files.
PHP
 Stream-based file operations.
PHP
 Handling file uploads.
PHP
 Checking if a file or directory exists.
PHP
 Creating, deleting, and manipulating files and directories.
PHP
 Getting path information and searching for files.
PHP
 Pattern matching with regular expressions.
PHP
 Replacing and splitting strings with regular expressions.
PHP
 Converting data to and from JSON.
PHP
 Checking variable existence and empty values.
PHP
 Determining variable types.
PHP
 Type conversion (casting).
PHP
 Managing sessions.
PHP
 Sending and retrieving cookies.
PHP
 Retrieving request data.
PHP
 Retrieving server and request information.
PHP
 Sending HTTP headers and status codes.
PHP
 Connecting to databases.
PHP
 Prepared statements for executing SQL.
PHP
 Retrieving query results.
PHP
 Controlling transactions.
PHP
 Basic syntax for exception handling.
PHP
 Error reporting and custom error handlers.
PHP
 Basic output.
PHP
 Debug output of variables.
PHP
 Output buffering.
PHP
 Hashing and verifying passwords.
PHP
 Generating hash values.
PHP
 Validating and sanitizing input values.
PHP
 Defining classes and creating instances.
PHP
 Access modifiers and static methods.
PHP
 Inheritance, interfaces, and abstract classes.
PHP
 Traits and special methods.
PHP
 Terminating or pausing a script.
PHP
 Defining and checking constants.
PHP
 Generating random numbers and unique IDs.
PHP
 Serializing data.
PHP
 Arrow function syntax with fn, added in PHP 7.4, and automatic capture of outer-scope variables.
PHP
 Comment syntax in // # /* */, when to write comments, and PHPDoc annotation format.
PHP
 Loose comparison with == and strict comparison with ===, and when to use each.
PHP
 Enumerations added in PHP 8.1 for type-safe definitions of fixed value sets.
PHP
 for loop syntax with initialization, condition, and update expressions in one statement.
PHP
 Iterating over arrays and associative arrays with foreach.
PHP
 Defining functions in PHP with default parameters, variadic arguments, and type declarations.
PHP
 Conditional branching with if, elseif, and else to execute different code paths.
PHP
 The four file-inclusion functions and how they differ when the target file is missing.
PHP
 Destructuring arrays into variables with list() and building associative arrays with compact().
PHP
 Symbol operators (&&, ||, !) versus keyword operators (and, or, not) and their precedence differences.
PHP
 match expression introduced in PHP 8, using strict comparison and returning a value directly.
PHP
 Preventing name collisions with namespace and importing symbols with use.
PHP
 Returning values from functions with return and using early returns for guard clauses.
PHP
 Multi-branch control flow with switch matching a single expression against multiple values.
PHP
 The ternary operator, Elvis shorthand ?:, null coalescing operator ??, and null coalescing assignment ??=.
PHP
 PHP's strict scope separation between functions and outer code, and how to use global and static.
PHP
 while loop for condition-based iteration and do-while loop that always executes at least once.
Python
 An overview of Python, its key features, how code is executed, and a recommended learning order for this dictionary.
Python
 Steps for installing Python and setting up an execution environment.
Python
 How to write and run .py files.
Python
 Basic built-in functions for getting length, type, and ID.
Python
 Output, input, and string representation.
Python
 Basic type conversion.
Python
 Generating sequences, adding indices, and parallel iteration.
Python
 Transforming, filtering, and sorting iterables.
Python
 Inspecting and retrieving object attributes.
Python
 Checking callability and working with iterators.
Python
 Opening files using a context manager.
Python
 Appending elements to a list.
Python
 Removing elements from a list.
Python
 Searching for and checking elements in a list.
Python
 Sorting and copying lists.
Python
 Concatenating, repeating, and slicing lists.
Python
 Syntax for generating a list in one line.
Python
 Converting between lists, tuples, and sets.
Python
 Splitting and joining strings.
Python
 Replacing substrings.
Python
 Removing whitespace or specific characters.
Python
 Converting between uppercase and lowercase.
Python
 Searching for and counting substrings.
Python
 Checking prefix, suffix, and containment.
Python
 Formatting strings.
Python
 Safe key retrieval and setting default values.
Python
 Retrieving keys, values, and key-value pairs.
Python
 Updating and deleting dictionary entries.
Python
 Copying, creating, and merging dictionaries.
Python
 Syntax for generating a dictionary in one line.
Python
 Adding and removing elements from a set.
Python
 Set operations: union, intersection, and difference.
Python
 Checking subset and superset relationships.
Python
 Absolute value, rounding, divmod, and exponentiation.
Python
 Square root, ceiling, and floor functions.
Python
 Mathematical constants, logarithms, and trigonometric functions.
Python
 Generating random numbers and making random selections.
Python
 Reading and writing text files.
Python
 Basic path operations.
Python
 Directory operations.
Python
 Modern path operations using pathlib.
Python
 Pattern matching with regular expressions.
Python
 Finding all matches of a pattern.
Python
 Substituting, splitting, and compiling regular expressions.
Python
 Converting between JSON strings and Python objects.
Python
 Reading and writing CSV files.
Python
 Creating date and time objects.
Python
 Formatting date and time values.
Python
 Calculating time durations and adding or subtracting from dates.
Python
 Command-line arguments, program exit, and path management.
Python
 Getting and setting environment variables.
Python
 Counting occurrences of elements.
Python
 Dictionaries with default values.
Python
 Double-ended queues and ordered dictionaries.
Python
 Chaining, slicing, and counting iterables.
Python
 Cartesian products, permutations, and combinations.
Python
 Grouping and aggregating iterables.
Python
 Aggregating values and partial function application.
Python
 Memoization and decorator utilities.
Python
 Determining variable types.
Python
 Batch evaluation of boolean conditions.
Python
 Basic syntax for exception handling.
Python
 Built-in exceptions such as ValueError, TypeError, and KeyError.
Python
 Raising exceptions and defining custom exceptions.
Python
 Defining classes and creating instances.
Python
 Properties, class methods, and static methods.
Python
 Inheritance and method overriding.
Python
 Special (dunder) methods.
Python
 Defining and using decorators.
Python
 Defining and using generators.
Python
 Defining anonymous functions.
Python
 Concurrent processing with threads.
Python
 Parallel processing with multiple processes.
Python
 Basics of asynchronous programming.
Python
 Making HTTP requests with the standard library.
Python
 Starting a simple HTTP server.
Python
 *args receives any number of positional arguments as a tuple; **kwargs receives keyword arguments as a dictionary.
Python
 Single-line comments use #; docstrings use triple quotes and are read by help() and documentation generators.
Python
 Defines functions with the def keyword; covers default values, keyword arguments, and positional/keyword-only parameters.
Python
 String interpolation syntax introduced in Python 3.6; embeds variables and expressions directly inside strings.
Python
 Iterates over each element of a sequence in order; any iterable value can be traversed.
Python
 global allows modifying global variables inside a function; nonlocal modifies variables in an enclosing scope from a nested function.
Python
 The basic conditional branching syntax; indentation defines blocks and conditions are evaluated top to bottom.
Python
 import loads a module; from ... import brings specific names into scope; as assigns an alias.
Python
 A membership test operator that checks whether an object is contained in a collection.
Python
 Checks object identity (same location in memory); also explains the difference from == (value equality).
Python
 Structural pattern matching syntax added in Python 3.10; branches based on the structure or content of a value.
Python
 The three basic operator types: arithmetic, comparison, and logical; also covers Python-specific syntax like chained comparisons.
Python
 pass is a no-op placeholder; break immediately exits a loop; continue skips the rest of the current iteration.
Python
 Returns a value from a function to the caller; tuples allow returning multiple values; early return enables guard clauses.
Python
 Annotates function arguments and return values with type information; not enforced at runtime but used by tools like mypy.
Python
 An assignment expression operator added in Python 3.8; returns a value as an expression while simultaneously assigning to a variable.
Python
 Loop constructs that repeat a block while a condition is true; while evaluates the condition first, do-while evaluates it after.
Python
 Safely manages resources using a context manager; ensures post-processing even if an exception occurs.
Ruby
 An overview of Ruby, its key features, how code is executed, and a recommended learning order for this dictionary.
Ruby
 Steps to set up an environment for installing and running Ruby.
Ruby
 How to write and run .rb files.
Ruby
 Getting the length of a string.
Ruby
 Checking string existence and prefix/suffix determination.
Ruby
 Getting the position of a substring.
Ruby
 Extracting a portion of a string.
Ruby
 Replacing strings.
Ruby
 Converting between uppercase and lowercase.
Ruby
 Removing whitespace and newlines.
Ruby
 Splitting a string and converting to an array.
Ruby
 Repeating and padding strings.
Ruby
 Converting a string to other types.
Ruby
 Checking and converting character encodings.
Ruby
 String formatting.
Ruby
 Adding and removing elements at the end or beginning of an array.
Ruby
 Adding, removing, and eliminating nil at arbitrary positions.
Ruby
 Checking element existence and searching positions.
Ruby
 Checking conditions and counting elements.
Ruby
 Transforming each array element to create a new array.
Ruby
 Extracting or excluding elements matching a condition.
Ruby
 Combining an array into a single value.
Ruby
 Unnesting, removing duplicates, and removing nil.
Ruby
 Sorting and reversing an array.
Ruby
 Concatenating arrays.
Ruby
 Getting a portion of an array.
Ruby
 Looping through an array.
Ruby
 Converting arrays to strings and computing Cartesian products.
Ruby
 Listing keys and values, and checking existence.
Ruby
 Getting, setting, deleting, and merging values.
Ruby
 Looping, transforming, and extracting from a hash.
Ruby
 Transforming a hash.
Ruby
 Advanced processing on a hash.
Ruby
 Converting number types.
Ruby
 Absolute values and rounding numbers.
Ruby
 Using mathematical functions and constants.
Ruby
 Iterating with integers.
Ruby
 Integer determination.
Ruby
 Basic operations on range objects.
Ruby
 Aggregating ranges and step iteration.
Ruby
 Pattern matching with regular expressions.
Ruby
 Searching strings with regular expressions.
Ruby
 Converting and using symbols.
Ruby
 Searching for elements that match a condition.
Ruby
 Getting minimum and maximum values.
Ruby
 Flattening, grouping, and aggregating.
Ruby
 Advanced iteration for splitting and combining.
Ruby
 Defining and calling blocks.
Ruby
 Creating and executing Proc and Lambda.
Ruby
 Using symbol's to_proc and method objects.
Ruby
 Reading and writing files.
Ruby
 Path manipulation and existence checks for files.
Ruby
 Directory operations.
Ruby
 Basic syntax for exception handling.
Ruby
 Major exception classes and defining custom exceptions.
Ruby
 Outputting to the console.
Ruby
 Debugging objects and checking types.
Ruby
 Defining classes, creating instances, and using accessors.
Ruby
 Setting access control (visibility).
Ruby
 Using self, instance variables, and class variables.
Ruby
 Using modules and mixins.
Ruby
 Class inheritance and calling parent methods.
Ruby
 Defining and using comparison operators.
Ruby
 A multi-branch syntax using === matching; accepts numbers, strings, ranges, regular expressions, and class names as conditions.
Ruby
 How to write single-line (#), multi-line (=begin...=end), and RDoc documentation comments in Ruby.
Ruby
 Defining methods with def; covers default values, keyword arguments, variadic args, block args, and ? / ! suffixes.
Ruby
 Two loop constructs in Ruby—for and each—with differences in block variable scoping explained.
Ruby
 How to make objects immutable with freeze and check frozen state with frozen? in Ruby.
Ruby
 Conditional branching in Ruby; covers trailing if/unless, early return, and the rule that only nil and false are falsy.
Ruby
 A hook triggered when an undefined method is called; use with respond_to_missing? to correctly implement dynamic methods.
Ruby
 nil is the sole instance of NilClass; only nil and false are falsy in Ruby conditions.
Ruby
 How to add methods to existing classes with open classes, and how to limit scope safely using Refinements.
Ruby
 The three categories of Ruby operators—arithmetic, comparison, and logical—many of which are methods and can be overloaded.
Ruby
 How to load standard libraries and gems with require, and load files by relative path with require_relative.
Ruby
 In Ruby, the last evaluated expression is automatically returned from a method when return is omitted.
Ruby
 The condition ? true_value : false_value syntax, when to use it versus trailing if, and combining with &. safe navigation.
Ruby
 while loops while a condition is true; until loops while it is false; also covers trailing form and loop do.
Rust
 An overview of Rust covering ownership, borrowing, and lifetimes, along with a recommended learning path through the dictionary pages.
Rust
 Comment syntax in // /// //! / /* */ /** */ /*! */, when to write comments, and when not to.
Rust
 Setup instructions for installing and running Rust.
Rust
 How to write, compile, and run .rs files.
Rust
 Declares variables and constants with mutability control.
Rust
 Rust's unique rule that each value has exactly one owner.
Rust
 A mechanism for referencing a value without taking ownership.
Rust
 An annotation that explicitly specifies the validity period of a reference.
Rust
 Duplicates a value and the mechanism for implicit copying.
Rust
 How resources are released when a scope ends.
Rust
 Conditional branching and pattern-matching branches.
Rust
 A syntax for branching a value across multiple patterns.
Rust
 Three patterns of repetitive processing.
Rust
 Defines and uses functions and closures.
Rust
 The three trait types of closures.
Rust
 A way to treat a function as a value.
Rust
 Defines a struct and creates an instance.
Rust
 A way to add methods to a struct.
Rust
 Creates an instance from an existing one and supports nesting.
Rust
 Commonly used derive attributes.
Rust
 Defines an enum and the kinds of variants it can have.
Rust
 Adds methods to an enum and branches with match.
Rust
 Practical patterns for using enums.
Rust
 Defines and implements a trait.
Rust
 A mechanism that requires a trait for a type parameter.
Rust
 Implements traits for string formatting.
Rust
 Traits for type conversion.
Rust
 A mechanism that abstracts types for reuse.
Rust
 Practical use of generics with constraints.
Rust
 An enum that represents the presence or absence of a value.
Rust
 Ways to extract a value from an Option.
Rust
 Transforms and chains Option values.
Rust
 An enum that represents success or failure.
Rust
 Extracts a Result value and propagates errors.
Rust
 How to define your own error type.
Rust
 Choosing between panics and recoverable errors.
Rust
 Ways to create a String.
Rust
 Concatenates and appends to strings.
Rust
 Gets the length, searches, and checks string values.
Rust
 Replaces, splits, and trims strings.
Rust
 Iterates over and converts strings.
Rust
 A reference to a portion of a string or array.
Rust
 Ways to create a Vec.
Rust
 Adds and removes elements.
Rust
 Retrieves, searches, and checks elements.
Rust
 Sorts, removes duplicates, concatenates, and splits.
Rust
 Commonly used utility macros.
Rust
 Creates a HashMap and inserts and retrieves entries.
Rust
 Checks for key existence, removes entries, and uses or_insert.
Rust
 Iterates and loops over a HashMap.
Rust
 Three ways to obtain an iterator.
Rust
 Transforms and filters elements.
Rust
 Terminal operations on an iterator for collecting and aggregating.
Rust
 Combines iterators.
Rust
 Fold operations and searching.
Rust
 Casts between primitive types and numeric conversions.
Rust
 Gives a type an alias or wraps it in a newtype.
Rust
 Macros for output and string generation.
Rust
 Reads from and writes to standard input and output.
Rust
 A simplified way to read and write files.
Rust
 Reads and writes using a File handle.
Rust
 Manipulates file paths.
Rust
 A smart pointer that places a value on the heap.
Rust
 Multiple ownership through reference counting.
Rust
 Runtime borrow checking for interior mutability.
Rust
 Combining multiple ownership with interior mutability.
Rust
 Spawns a thread and waits for it to finish.
Rust
 A mechanism for safely sharing data between threads.
Rust
 Message passing between threads.
SQL
 An overview of SQL, features and trade-offs, key feature explanations, and a recommended learning order for this dictionary.
SQL
 Steps for setting up an environment to execute SQL.
SQL
 How to write .sql files and execute them in each database.
SQL
 Basic syntax for retrieving rows and columns.
SQL
 Filtering rows by condition.
SQL
 Logical operators for combining multiple conditions.
SQL
 Pattern-matching search.
SQL
 Checking for NULL values.
SQL
 Sorting query results.
SQL
 Specifying the number of rows to retrieve and the starting position.
SQL
 Inserting rows into a table.
SQL
 Updating existing rows.
SQL
 Deleting rows from a table.
SQL
 Quickly deleting all rows from a table.
SQL
 Counting the number of rows or records.
SQL
 Calculating sums and averages.
SQL
 Finding maximum and minimum values.
SQL
 Grouping data and filtering aggregated results.
SQL
 Joining rows that match in both tables.
SQL
 Joining while keeping all rows from one table.
SQL
 Joining while keeping all rows from both tables.
SQL
 A Cartesian product join that generates all combinations.
SQL
 Joining a table with itself.
SQL
 Subqueries that return a single value or row.
SQL
 Checking for matches against subquery results.
SQL
 Comparing against all or any values returned by a subquery.
SQL
 Subqueries that reference the outer query.
SQL
 Vertically combining results from multiple SELECT statements.
SQL
 Extracting common rows or the difference between result sets.
SQL
 Basic syntax for window functions.
SQL
 Assigning ranks and sequential numbers to rows.
SQL
 Referencing values from preceding or following rows.
SQL
 Calculating running totals and moving averages.
SQL
 Concatenating strings and getting their length.
SQL
 Extracting substrings and trimming leading/trailing whitespace.
SQL
 Converting case and replacing strings.
SQL
 Searching for character positions and checking pattern matches.
SQL
 Rounding numeric values.
SQL
 Absolute values, modulo, and exponentiation.
SQL
 Getting the current date and time.
SQL
 Adding/subtracting dates and calculating date differences.
SQL
 Extracting year, month, day, etc. from a date and formatting it.
SQL
 Switching values based on conditional logic.
SQL
 Replacing NULL with another value.
SQL
 Converting data types.
SQL
 Creating a table.
SQL
 Basic column-level constraints.
SQL
 Primary key and foreign key constraints.
SQL
 Modifies the definition of an existing table.
SQL
 Creates or drops an index on a table.
SQL
 Creates, updates, or drops a view.
SQL
 Improves query readability using Common Table Expressions.
SQL
 Begins, commits, or rolls back a transaction.
SQL
 Grants or revokes privileges for a user.
SQL
 Displays the execution plan of a query.
SQL
 A feature that automatically assigns sequential numbers to a primary key column; MySQL uses AUTO_INCREMENT, PostgreSQL uses SERIAL, SQL Server uses IDENTITY.
SQL
 An operator that specifies an inclusive range condition; usable with numbers, dates, and strings.
SQL
 Three comment types: single-line (--), MySQL-only single-line (#), and block comments (/* */).
SQL
 An overview of major SQL data types including numeric, string, date, and boolean types, with notes on differences across DBMSes.
SQL
 Aggregate functions that concatenate multiple row values within a group into a single string; MySQL uses GROUP_CONCAT, PostgreSQL and SQL Server use STRING_AGG.
SQL
 Shortcut functions that return different values based on a condition; MySQL uses IF(), SQL Server uses IIF().
SQL
 Syntax for bulk-inserting the results of a SELECT statement into another table, used for copying data between tables or filtered extraction.
Swift
 An overview of Swift, its features, and how execution works, along with a recommended learning path through the dictionary.
Swift
 Comment syntax in // / /* */, when to write comments, and when not to.
Swift
 Steps to set up an environment for installing and running Swift.
Swift
 How to write and run .swift files.
Swift
 Declaring constants and variables with type inference.
Swift
 Grouping multiple values together.
Swift
 Basic string operations.
Swift
 Converting between uppercase and lowercase.
Swift
 String determination and checking.
Swift
 Replacing and trimming strings.
Swift
 Splitting, joining, and index operations on strings.
Swift
 Adding, inserting, and removing array elements.
Swift
 Searching and checking within an array.
Swift
 Filtering and sorting an array.
Swift
 Transforming array elements.
Swift
 Aggregating and enumerating an array.
Swift
 Slicing and concatenating arrays.
Swift
 Declaring and accessing a dictionary.
Swift
 Updating, deleting, and transforming a dictionary.
Swift
 Basic set operations.
Swift
 Set operations such as union and intersection.
Swift
 Conditional branching with pattern matching.
Swift
 Basic loop constructs.
Swift
 Controlling loops and functions.
Swift
 Conditional checking with early return.
Swift
 Defining functions and rules for arguments.
Swift
 Advanced use of inout parameters and return values.
Swift
 Basic closure syntax.
Swift
 Writing closures concisely using trailing closure syntax.
Swift
 Advanced topics on closures.
Swift
 Basics of Optional (safely handling nil).
Swift
 Safely unwrapping an Optional.
Swift
 Calling methods and transforming Optional values.
Swift
 Returning a default value when nil is encountered.
Swift
 Checking and converting types.
Swift
 Defining and using enumerations.
Swift
 Enumerations with raw values.
Swift
 Enumerations with associated values.
Swift
 Adding methods to an enumeration.
Swift
 Defining structs and characteristics of value types.
Swift
 Defining classes and characteristics of reference types.
Swift
 Class inheritance and method overriding.
Swift
 Types of properties and how to use them.
Swift
 Special initializers.
Swift
 Giving a type an alias.
Swift
 Defining and adopting protocols.
Swift
 Advanced use of protocols.
Swift
 Extending existing types.
Swift
 Conforming to a protocol using an extension.
Swift
 JSON encoding and decoding.
Swift
 Using standard protocols.
Swift
 Writing generic functions independent of specific types.
Swift
 Generic structs, classes, and enums.
Swift
 Type abstraction syntax in Swift 5.7+.
Swift
 Defining custom errors.
Swift
 Throwing and catching errors.
Swift
 Treating success and failure as values.
Swift
 How ARC works and patterns that cause retain cycles.
Swift
 Preventing retain cycles with weak and unowned references.
Swift
 Defining and calling asynchronous functions.
Swift
 Managing tasks and running them in parallel.
Swift
 Data protection with actors and usage of @MainActor.
Swift
 Manipulating dates and times.
Swift
 Building URLs and making HTTP requests.
Swift
 JSON decoding and encoding.
Swift
 File and directory operations.
Swift
 Persisting app settings and small data.
Swift
 Event notification between objects.
Swift
 Timer processing.
TypeScript
 An overview of TypeScript, differences from JavaScript, pros and cons, and a recommended learning order for this dictionary.
TypeScript
 Comment syntax in // / /* */, when to write comments, and when not to.
TypeScript
 Setup instructions for installing and running TypeScript.
TypeScript
 How to write, compile, and run .ts files.
TypeScript
 The three major primitive types in TypeScript.
TypeScript
 Three types that represent the absence of a value.
TypeScript
 Special types related to type safety.
TypeScript
 Fundamentals of composite types.
TypeScript
 Enumeration types.
TypeScript
 Where to write types and how automatic type inference works.
TypeScript
 Type aliases.
TypeScript
 Defines the shape of an object type.
TypeScript
 A type that is either A or B.
TypeScript
 A type that is both A and B.
TypeScript
 Uses a specific value itself as a type.
TypeScript
 Uses a string pattern as a type.
TypeScript
 Conditional branching at the type level.
TypeScript
 Generates a new type from an existing type.
TypeScript
 A mechanism that accepts a type as a parameter.
TypeScript
 Adds constraints to a type parameter.
TypeScript
 Applies generics to classes and interfaces.
TypeScript
 Operators that work at the type level.
TypeScript
 Extracts a property of a type as a type.
TypeScript
 Makes all properties optional or required.
TypeScript
 Makes properties read-only.
TypeScript
 Selects or excludes specific properties from a type.
TypeScript
 An object type with specified key and value types.
TypeScript
 Filters union types.
TypeScript
 Utility types for functions and null-related operations.
TypeScript
 Narrows the type of primitive values.
TypeScript
 Narrows the type of class instances.
TypeScript
 Narrows the type by checking for property existence.
TypeScript
 Creates a custom type guard function.
TypeScript
 A type guard that throws an error when a condition is not met.
TypeScript
 Defines a class in TypeScript.
TypeScript
 Restricts the access scope of class members.
TypeScript
 A base class that enforces implementation in subclasses.
TypeScript
 Implements an interface in a class.
TypeScript
 Safely overrides a method from a parent class.
TypeScript
 Type annotations for asynchronous processing.
TypeScript
 Imports or exports only type information.
TypeScript
 How type declaration files work.
TypeScript
 TypeScript-specific module management.
TypeScript
 Infers and extracts types within conditional types.
TypeScript
 A type that references itself.
TypeScript
 Built-in utility types for string manipulation.
TypeScript
 Performs type checking while preserving type inference.
TypeScript
 A configuration file that controls compiler behavior.
TypeScript
 Individual flags enabled by strict: true.
TypeScript
 TypeScript class syntax covering type annotations on properties, constructors, and methods, access modifiers, shorthand parameter properties, and abstract classes.
TypeScript
 A metaprogramming feature applied with @name to classes, methods, and properties; widely used in frameworks like Angular and NestJS.
TypeScript
 A loop syntax that iterates over iterables such as arrays, Maps, Sets, strings, and Generators, with automatic type inference for each element.
TypeScript
 TypeScript loop constructs covering for, while, do-while, and flow control with break, continue, and labeled statements.
TypeScript
 Type annotations for function declarations, function expressions, and arrow functions, including optional parameters, default values, rest parameters, and overload signatures.
TypeScript
 TypeScript conditional branching syntax, which works together with type narrowing to automatically narrow variable types inside condition blocks.
TypeScript
 Basic syntax for sharing code and types between TypeScript modules, covering named exports, default exports, and re-exports.
TypeScript
 TypeScript switch statement that automatically narrows types when used with discriminated unions and allows exhaustiveness checking with the never type.
TypeScript
 TypeScript exception handling syntax where the catch clause argument is typed as unknown and narrowed using instanceof or type guards.
TypeScript
 How to write type annotations on variables, parameters, and return values, covering primitive types, array types, and inline object type annotations.
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