The provided bash script is a comprehensive multirun tool for Ollama language models, which allows users to run prompts against multiple models and save the outputs as web pages. Here's a breakdown of its features and structure:

1. **Script Structure**:
   - The script begins with a shebang (`#!/usr/bin/env bash`), followed by comments detailing the purpose, usage, and available flags.
   - It defines several functions (e.g., `usage`, `parseCommandLine`, etc.) to handle different aspects of the script's functionality.

2. **Function Descriptions**:
   - `usage()`: Displays help information.
   - `parseCommandLine()`: Parses command-line arguments, including flags for models, output directory, timeout, and version display.
   - `getDateTime()`: Retrieves the current date and time.
   - `setModels()`: Lists available Ollama models and validates user input for specific models.
   - `safeString()`: Cleans up the prompt by truncating it, converting to lowercase, replacing spaces with underscores, and removing non-allowed characters.
   - `createOutputDirectory()`: Creates a subdirectory for storing output files based on a unique tag and timestamp.
   - `setPrompt()`: Prompts users to enter a prompt via terminal input or redirects from standard input (pipe/file).
   - `savePrompt()`: Writes the prompt, along with other metadata, to text files.
   - `generatePromptYaml()`: Creates a YAML file for storing the prompt.
   - `textarea()`: Generates an HTML textarea element for displaying input content.
   - `showPrompt()`: Displays the prompt and related statistics in an HTML format.
   - `showImages()`: Lists images generated during model evaluation, if any.

3. **Additional Features**:
   - `clearModel()`: Clears a model's session context using Expect commands.
   - `stopModel()`: Stops a running model using Ollama's command-line interface.
   - `setStats()`: Collects and processes statistical information about the models' performance.
   - `showSystemStats()`: Displays system details, including architecture, processor, OS, memory used, and OS version.
   - `createModelInfoTxt()`: Generates model information text files for each specified model.
   - `setModelInfo()`: Parses model info text files to extract relevant data (architecture, parameters, context length, etc.).
   - `createModelsOverviewHtml()`: Creates an HTML page listing all used models with their details.
   - `createModelOutputHtml()`: Generates individual model output pages containing the raw output, stats, and statistics.
   - `createOutputIndexHtml()`: Creates an index of model outputs grouped by run directory.
   - `addModelToOutputIndexHtml()`: Populates the output index page with links to individual model runs.
   - `finishOutputIndexHtml()`: Completes the output index HTML page.

4. **Execution**:
   - The script concludes with a call to the main functionality: parsing command-line arguments, setting up models, prompts, and output directories, then running each specified prompt against all Ollama models, collecting stats, generating output pages, and indexing them appropriately.

Overall, this script is well-structured, modular, and provides extensive functionality for running multiple Ollama model evaluations with customizable prompts and detailed reporting. It's a powerful tool for users working with language models.