Shell Mastery

Optimize shell configurations and scripts to meet strict performance and defensive targets.

Shell Selection & Performance

| Use Case | Shell | Key Choice Reason | |----------|-------|--------------------| | System Automation | Bash | Universal container/VM compatibility | | Interactive Dev | Zsh | Native macOS shell, rich completions | | Windows/Cloud | PowerShell | Object pipeline, native .NET APIs |

• Interactive Startup Target: 0.1s - 0.5s. Profile slow shells with Zsh zprof or PowerShell Measure-Command.
• Fuzzy Search Latency:

Core Scripting & Config Snippets

1. Defensive Bash (Fail-Fast)

#!/bin/bash
set -euo pipefail
trap cleanup EXIT INT TERM
cleanup() { rm -f "$TEMP_FILE"; }

2. Portable Argument Parsing (POSIX)

while [ $# -gt 0 ]; do
    case "$1" in
        -h|--help) show_help; exit 0 ;;
        -v|--verbose) VERBOSE=1 ;;
        *) echo "Unknown option: $1" >&2; exit 1 ;;
    esac
    shift
done

3. Zsh Lazy-Loading & Async Plugins

# Lazy-load NVM
nvm() { unset -f nvm node npm; [ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh"; nvm "$@"; }

# Async plugins via Zinit
zinit ice wait lucid
zinit light zsh-users/zsh-autosuggestions

4. PowerShell Parallelism

1..100 | ForEach-Object -Parallel { # Parallel work } -ThrottleLimit 10

Deep-Dive Reference Manuals

• Read [performance-optimization.md](references/performance-optimization.md) to diagnose slow shells, lazy-load SDKs, or profile startup latency.
• Read [defensive-scripting.md](references/defensive-scripting.md) when writing production scripts requiring signal traps, file locking, or strict error checking.
• Read [portability.md](references/portability.md) to rewrite Bashisms into POSIX-compliant syntax for Alpine/minimal containers.
• Read [modern-toolkit.md](references/modern-toolkit.md) to configure fzf, tmux, Atuin, ripgrep, bat, or eza aliases.
• Read [zsh-optimization.md](references/zsh-optimization.md) to customize ZLE widgets, completion styles, or advanced glob qualifiers.
• Read [powershell-patterns.md](references/powershell-patterns.md) for object-oriented pipelines, ThreadJobs, and secure credential handling.

• Scripts MUST use defensive patterns (set -euo pipefail) to fail fast.
• Non-critical plugins and SDK initializers (e.g. NVM, Conda) SHOULD be lazy-loaded.
• Always verify shell compatibility (POSIX vs Bash/Zsh specific features) before execution.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: JosephSanjaya
• Source: JosephSanjaya/skills
• License: MIT

Install and usage instructions live in the source repository linked above.