nanobot-runtime/skills/bash/SKILL.md

name, description

name	description
bash	Bash / shell script conventions and tooling. Use for anything involving shell scripts.

Bash Script Conventions

Shebang and Strict Mode

• #!/usr/bin/env bash for portability.
• set -euo pipefail on the line after shebang (separated by a blank line).
• Hooks that check exit codes intentionally may omit set -e.

Functions

• Declare local variables with local; never leak into global scope.
• Use readonly for values that must not change.
• Return data via stdout; capture with $(fn). Do not use global variables for return values.

Variables and Conditionals

• Always double-quote expansions and command substitutions: "$var", "${var}", "$(cmd)", "$@".
• Use ${var:-default} for defaults, ${var:?error msg} for required values.
• Use arrays for lists of values — do not split strings with IFS.
• Use [[ ]] instead of [ ].
• Check command existence with command -v cmd &> /dev/null, not which.

Output and Exit Codes

• Diagnostic/error messages go to stderr: echo "error: ..." >&2.
• Hook scripts use exit 0 (pass) and exit 2 (block). Do not use exit 1.

Files and Paths

• Resolve script directory: script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)".
• Temporary files: tmp=$(mktemp) with cleanup via trap 'rm -f "$tmp"' SIGINT SIGTERM ERR EXIT.

ShellCheck

• All scripts must pass shellcheck.
• To suppress a check: # shellcheck disable=SCxxxx with a comment explaining why.