Command

/ˈwɒtɪz/

noun — "a structured explanation of a term, concept, or technology."

Whatis refers to the format, system, or page type designed to provide a comprehensive definition of a specific term, concept, technology, or process in computing, electronics, cryptography, or related fields. It is not merely a dictionary entry; instead, a whatis page is crafted to give the reader a deep, in-context understanding of the term, including its practical applications, technical details, history, relationships to other concepts, and real-world examples.

/juːˈniːk/

noun or command … “filtering adjacent duplicates.”

uniq is a classic UNIX command-line utility used to detect, filter, or report repeated lines in a text stream. Its defining trait is subtle but crucial: it only works on adjacent duplicate lines. If identical lines are separated by other content, uniq will treat them as different unless the data is preprocessed.

/ˈoʊpən/

verb … “to make a resource accessible for use by a program or user.”

open is a fundamental operation in computing that establishes access to a resource so it can be read, written, executed, or interacted with. The resource may be a file, network connection, device, stream, or application-level object. Calling open does not usually perform the work itself; instead, it prepares the system state so that subsequent operations can safely and predictably occur.

/rɪˈsiːv/

verb … “to accept or collect data or messages sent from another system, process, or user.”

/sɛnd/

verb … “to transmit data or a message from one system or process to another.”

/ˈɒnˌloʊd/

noun … “an event that triggers when a web page or resource finishes loading.”

onload is an event handler in web development that executes a specified function when a document, image, or other resource has fully loaded in the browser. It is commonly used in HTML, JavaScript, and related web technologies to initialize scripts, perform setup tasks, or manipulate the DOM after all content and dependencies are available. By ensuring that code runs only after resources are ready, onload helps prevent errors and improves user experience.

/krɒn/

noun … “a time-based scheduler that automates recurring tasks on Unix-like systems.”

cron is a Unix daemon that executes scheduled commands or scripts at specified intervals, allowing automation of repetitive system tasks such as backups, log rotation, email notifications, and maintenance routines. Users define scheduled tasks in a configuration file called a crontab, which specifies the timing and command to execute using a concise syntax representing minutes, hours, days, months, and weekdays.

/ɑːrˈsɪŋk/

noun … “a fast and versatile tool for synchronizing files and directories between locations.”

rsync is a Unix utility that synchronizes files and directories efficiently across local and remote systems. It minimizes data transfer by using a delta encoding algorithm, which only copies differences between the source and destination, rather than the entire file. This makes rsync highly efficient for backups, deployments, and mirroring large datasets over networks.

/sɔːrt/

noun … “a Unix command that arranges lines of text in a specified order.”

sort is a command-line utility in Unix-like operating systems used to organize lines of text in files or streams based on lexicographical, numerical, or custom criteria. By default, it arranges lines in ascending lexicographic order, but it supports options for reverse order, numerical sorting, and key-based sorting. This makes sort an essential tool for data organization, preprocessing, and analysis in shell workflows.

/ɛl ɛs/

noun … “a Unix command that lists directory contents.”

ls is a standard Unix command-line utility used to display the contents of a directory, including files, subdirectories, and metadata such as permissions, ownership, and timestamps. It provides users with an immediate view of the filesystem structure and allows sorting, formatting, and filtering of entries through various options and flags.