Standard bash script template with unofficial strict mode

template.bash

#! /usr/bin/env bash
set -o errexit -o nounset -o errtrace -o pipefail
IFS=$'\n\t'
shopt -s nullglob
# shellcheck disable=SC2154
trap 's=$?; echo >&2 "$0: Error on line "$LINENO": $BASH_COMMAND"; exit $s' ERR

warn() { [ $# -ge 1 ] && printf >&2 "%s\n" "$*"; }

main() {
    echo Hello World!
}

main
warn Exiting ...

exit 0

Sources:

• Use Bash Strict Mode (Unless You Love Debugging) by Aaron Maxwell
• Bash strict mode and why you should care by @olivergondza

Tools:

• ShellCheck - finds bugs in your shell scripts, by @koalaman
• Shellharden by @anordal
  • Shellharden / Safe ways to do things in bash
• shfmt, part of sh – A shell parser, formatter, and interpreter by @mvdan

Further reading:

• Filenames and Pathnames in Shell: How to do it Correctly by David A. Wheeler 2020-02-22 (original version 2010-05-19)
• Bash Pitfalls and BashFAQ by GreyCat (Greg)