bash-dotfiles

name	bash-dotfiles
description	Expert knowledge of bash scripting standards for this dotfiles repo. Covers mandatory header, safety flags, variable quoting, banned patterns, and modern tool idioms (rg/fd/bat/eza/jaq). Use when writing or reviewing any .sh file in Home/.local/bin/ or shell config files.

Bash Dotfiles Standards

Mandatory Script Header

#!/usr/bin/env bash
set -euo pipefail

has() { command -v -- "$1" &>/dev/null; }
die() { printf '\e[31mERROR: %s\e[0m\n' "$*" >&2; exit 1; }
log() { printf '\e[34mINFO: %s\e[0m\n' "$*"; }

Every script in Home/.local/bin/ MUST start with exactly this header. No exceptions.

Safety Rules

• set -euo pipefail — always present, on line 2
• [[ ]] not [ ] — bash-native conditionals only
• Quote every variable: "${var}" not $var
• No eval — use arrays/functions/parameter expansion
• No backtick substitution — use $(cmd) only
• No ls parsing — use globs or fd

Variable & String Idioms

# File contents (no cat subshell)
content=$(<"${file}")

# Array from file
mapfile -t lines < "${file}"

# String trim suffix/prefix
base="${path%.*}"
dir="${path%/*}"
upper="${var^^}"

# ANSI colors (no tput)
RED=$'\e[31m'; RESET=$'\e[0m'
printf '%s%s%s\n' "${RED}" "error text" "${RESET}"

Tool Fallback Chain

Always try modern tool first, fall back to legacy:

if has rg; then
  rg -l "pattern" .
elif has grep; then
  grep -rl "pattern" .
fi

if has fd; then
  fd -e sh .
else
  find . -name "*.sh"
fi

Performance

• Cache command -v results outside loops: has_rg=$(has rg && echo 1 || echo 0)
• Batch I/O: xargs -P "$(nproc)" for parallel jobs
• Use grep -F for literal string matching (no regex overhead)
• Use associative arrays for O(1) lookups instead of repeated grep

Script Placement

• New utility scripts → Home/.local/bin/scriptname.sh
• Must be executable: chmod +x
• Must pass: shellcheck -x scriptname.sh and shfmt -d -i 2 scriptname.sh