Shell — Shell Scripting Reference

Quick-reference skill for Bash shell scripting, built-in features, and best practices.

When to Use

• - Writing reliable Bash scripts with proper error handling
• Understanding redirections, pipes, and process substitution
• Managing signals, traps, and background processes
• Debugging shell scripts with set options and tracing
• Choosing between shell features and external tools

Commands

intro

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Overview of shell scripting — Bash features, shebang, execution, portability.

variables

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Variables — declaration, scope, arrays, parameter expansion, special variables.

control

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Control flow — if/else, case, for, while, until, select, functions.

redirections

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Redirections and pipes — stdin/stdout/stderr, heredocs, process substitution.

safety

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Safety practices — set -euo pipefail, quoting, shellcheck, error handling.

tools

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Essential tools — awk, sed, grep, find, xargs, cut, sort, jq patterns.

signals

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Signals and traps — SIGTERM, SIGINT, cleanup handlers, background jobs.

checklist

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Shell script quality checklist.

help

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version

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Configuration