Shell scripting instructions for bash, sh, zsh, and other shells (#389)

* shell scripting instructions

Signed-off-by: Brooke Hamilton <45323234+brooke-hamilton@users.noreply.github.com>

* parsing guidelines

Signed-off-by: Brooke Hamilton <45323234+brooke-hamilton@users.noreply.github.com>

---------

Signed-off-by: Brooke Hamilton <45323234+brooke-hamilton@users.noreply.github.com>

docs/README.instructions.md

@@ -106,6 +106,7 @@ Team and project-specific instructions to enhance GitHub Copilot's behavior for
 | [Rust MCP Server Development Best Practices](../instructions/rust-mcp-server.instructions.md)<br />[![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Frust-mcp-server.instructions.md)<br />[![Install in VS Code Insiders](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Frust-mcp-server.instructions.md) | Best practices for building Model Context Protocol servers in Rust using the official rmcp SDK with async/await patterns |
 | [Secure Coding and OWASP Guidelines](../instructions/security-and-owasp.instructions.md)<br />[![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fsecurity-and-owasp.instructions.md)<br />[![Install in VS Code Insiders](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fsecurity-and-owasp.instructions.md) | Comprehensive secure coding instructions for all languages and frameworks, based on OWASP Top 10 and industry best practices. |
 | [Self-explanatory Code Commenting Instructions](../instructions/self-explanatory-code-commenting.instructions.md)<br />[![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fself-explanatory-code-commenting.instructions.md)<br />[![Install in VS Code Insiders](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fself-explanatory-code-commenting.instructions.md) | Guidelines for GitHub Copilot to write comments to achieve self-explanatory code with less comments. Examples are in JavaScript but it should work on any language that has comments. |
+| [Shell Scripting Guidelines](../instructions/shell.instructions.md)<br />[![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fshell.instructions.md)<br />[![Install in VS Code Insiders](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fshell.instructions.md) | Shell scripting best practices and conventions for bash, sh, zsh, and other shells |
 | [Spec Driven Workflow v1](../instructions/spec-driven-workflow-v1.instructions.md)<br />[![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fspec-driven-workflow-v1.instructions.md)<br />[![Install in VS Code Insiders](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fspec-driven-workflow-v1.instructions.md) | Specification-Driven Workflow v1 provides a structured approach to software development, ensuring that requirements are clearly defined, designs are meticulously planned, and implementations are thoroughly documented and validated. |
 | [Spring Boot Development](../instructions/springboot.instructions.md)<br />[![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fspringboot.instructions.md)<br />[![Install in VS Code Insiders](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fspringboot.instructions.md) | Guidelines for building Spring Boot base applications |
 | [SQL Development](../instructions/sql-sp-generation.instructions.md)<br />[![Install in VS Code](https://img.shields.io/badge/VS_Code-Install-0098FF?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fsql-sp-generation.instructions.md)<br />[![Install in VS Code Insiders](https://img.shields.io/badge/VS_Code_Insiders-Install-24bfa5?style=flat-square&logo=visualstudiocode&logoColor=white)](https://aka.ms/awesome-copilot/install/instructions?url=vscode-insiders%3Achat-instructions%2Finstall%3Furl%3Dhttps%3A%2F%2Fraw.githubusercontent.com%2Fgithub%2Fawesome-copilot%2Fmain%2Finstructions%2Fsql-sp-generation.instructions.md) | Guidelines for generating SQL statements and stored procedures |

instructions/shell.instructions.md

@@ -0,0 +1,132 @@
+---
+description: 'Shell scripting best practices and conventions for bash, sh, zsh, and other shells'
+applyTo: '**/*.sh'
+---
+
+# Shell Scripting Guidelines
+
+Instructions for writing clean, safe, and maintainable shell scripts for bash, sh, zsh, and other shells.
+
+## General Principles
+
+- Generate code that is clean, simple, and concise
+- Ensure scripts are easily readable and understandable
+- Add comments where helpful for understanding how the script works
+- Generate concise and simple echo outputs to provide execution status
+- Avoid unnecessary echo output and excessive logging
+- Use shellcheck for static analysis when available
+- Assume scripts are for automation and testing rather than production systems unless specified otherwise
+- Prefer safe expansions: double-quote variable references (`"$var"`), use `${var}` for clarity, and avoid `eval`
+- Use modern Bash features (`[[ ]]`, `local`, arrays) when portability requirements allow; fall back to POSIX constructs only when needed
+- Choose reliable parsers for structured data instead of ad-hoc text processing
+
+## Error Handling & Safety
+
+- Always enable `set -euo pipefail` to fail fast on errors, catch unset variables, and surface pipeline failures
+- Validate all required parameters before execution
+- Provide clear error messages with context
+- Use `trap` to clean up temporary resources or handle unexpected exits when the script terminates
+- Declare immutable values with `readonly` (or `declare -r`) to prevent accidental reassignment
+- Use `mktemp` to create temporary files or directories safely and ensure they are removed in your cleanup handler
+
+## Script Structure
+
+- Start with a clear shebang: `#!/bin/bash` unless specified otherwise
+- Include a header comment explaining the script's purpose
+- Define default values for all variables at the top
+- Use functions for reusable code blocks
+- Create reusable functions instead of repeating similar blocks of code
+- Keep the main execution flow clean and readable
+
+## Working with JSON and YAML
+
+- Prefer dedicated parsers (`jq` for JSON, `yq` for YAML—or `jq` on JSON converted via `yq`) over ad-hoc text processing with `grep`, `awk`, or shell string splitting
+- When `jq`/`yq` are unavailable or not appropriate, choose the next most reliable parser available in your environment, and be explicit about how it should be used safely
+- Validate that required fields exist and handle missing/invalid data paths explicitly (e.g., by checking `jq` exit status or using `// empty`)
+- Quote jq/yq filters to prevent shell expansion and prefer `--raw-output` when you need plain strings
+- Treat parser errors as fatal: combine with `set -euo pipefail` or test command success before using results
+- Document parser dependencies at the top of the script and fail fast with a helpful message if `jq`/`yq` (or alternative tools) are required but not installed
+
+```bash
+#!/bin/bash
+
+# ============================================================================
+# Script Description Here
+# ============================================================================
+
+set -euo pipefail
+
+cleanup() {
+    # Remove temporary resources or perform other teardown steps as needed
+    if [[ -n "${TEMP_DIR:-}" && -d "$TEMP_DIR" ]]; then
+        rm -rf "$TEMP_DIR"
+    fi
+}
+
+trap cleanup EXIT
+
+# Default values
+RESOURCE_GROUP=""
+REQUIRED_PARAM=""
+OPTIONAL_PARAM="default-value"
+readonly SCRIPT_NAME="$(basename "$0")"
+
+TEMP_DIR=""
+
+# Functions
+usage() {
+    echo "Usage: $SCRIPT_NAME [OPTIONS]"
+    echo "Options:"
+    echo "  -g, --resource-group   Resource group (required)"
+    echo "  -h, --help            Show this help"
+    exit 0
+}
+
+validate_requirements() {
+    if [[ -z "$RESOURCE_GROUP" ]]; then
+        echo "Error: Resource group is required"
+        exit 1
+    fi
+}
+
+main() {
+    validate_requirements
+
+    TEMP_DIR="$(mktemp -d)"
+    if [[ ! -d "$TEMP_DIR" ]]; then
+        echo "Error: failed to create temporary directory" >&2
+        exit 1
+    fi
+    
+    echo "============================================================================"
+    echo "Script Execution Started"
+    echo "============================================================================"
+    
+    # Main logic here
+    
+    echo "============================================================================"
+    echo "Script Execution Completed"
+    echo "============================================================================"
+}
+
+# Parse arguments
+while [[ $# -gt 0 ]]; do
+    case $1 in
+        -g|--resource-group)
+            RESOURCE_GROUP="$2"
+            shift 2
+            ;;
+        -h|--help)
+            usage
+            ;;
+        *)
+            echo "Unknown option: $1"
+            exit 1
+            ;;
+    esac
+done
+
+# Execute main function
+main "$@"
+
+```