Ordinalsed

Ordinalsed is a command-line text processing tool that extends the traditional stream editor model by introducing ordinal-based addressing. It enables operations such as substitution, deletion, or insertion to be targeted by ordinal positions, including the first, second, third, last, or any Nth occurrence of a pattern, either within each line or across the entire input. The goal is to make precise text transformations that rely on the position of a pattern rather than solely its presence.

Origin and design of ordinalsed trace a lineage to scripting and text-processing needs in software development and data preparation. Conceptually it arose from discussions about simplifying tasks that require exact ordinal control, and it is typically positioned as a companion or extension to sed, designed to interoperate with standard shells and pipelines. The project is usually described as experimental or community-maintained, with an emphasis on small-footprint operation and streaming performance.

Features and syntax commonly associated with ordinalsed include ordinal selectors such as first, second, third, last, and numeric values indicating the Nth occurrence. It supports common text-editing operations like substitution, deletion, and insertion, and can be applied per line or across the entire input. The tool is designed to be compatible with familiar sed-like workflows while introducing explicit ordinal targeting. Scripts can often be composed to combine multiple operations in a single pass, leveraging standard input and output semantics.

Examples illustrate the core idea: to substitute the first occurrence of a term, a command might resemble ordinalsed 's/error/ERROR/first' log.txt; to address the third occurrence, ordinalsed 's/error/ERROR/3' log.txt; to remove the last occurrence of a pattern, ordinalsed 'd/pattern/last' log.txt. The exact syntax can vary by implementation, but the ordinal-targeting concept remains central.

See also: sed, awk, perl, text processing tools.