NHS Number command line interface

A National Health Service (NHS) Number is a unique ten-digit identifier allocated to registered patients of NHS England and the NHS Isle of Man.

This tool is a command line interface that parses each standard input line into an NHS number, then validates the check digit is correct.

• If the line is a valid NHS number, then print it.

• If the line is an invalid NHS Number, or is unparseable, then print an error message.

• If the line is blank, then skip it.

References:

• National Health Service (NHS)

• NHS Number

Examples

Suppose you have a text file input.txt that contains one NNS Number per line, and some may be valid or invalid:

999 999 9999
999 123 4561

If you use Linux or macOS, then here's how to parse each line and validate it:

cat input.txt | nhs-number-cli

If you use Windows, then here's how to parse each line and validate it:

type input.txt | nhs-number-cli.exe

The commmand prints the valid NHS Number to stdout:

999 999 9999

The commmand prints the invalid NHS Number to stderr:

Error invalid line 1. Error: validate check digit failed. NHS Number: 999 123 4561

Releases

You can build a release for your own platform:

cargo build --release

You can download a prebuilt release for Windows:

• Windows with GNU: <target/x86_64-pc-windows-gnu/release/nhs-number-cli.exe>

We aim to add more prebuilt releases soon.

Documentation

Full documentation lives under docs/:

• About NHS Numbers
• Installation
• Usage
• Examples
• Troubleshooting
• Architecture
• Development
• FAQ

Runnable examples with expected-output fixtures and run.sh scripts live under examples/. Run them all with:

cargo build
./examples/run-all.sh

For AI coding agents

See AGENTS.md for conventions, the behavioural contract, and things to avoid when modifying this repository with the help of AI tools.