Bash script template

template.bash

#!/usr/bin/env bash

# https://kvz.io/bash-best-practices.html
set -o errexit
set -o pipefail
set -o nounset

# DEBUG
#set -o xtrace

__file="${BASH_SOURCE[0]}"
__real_file="$(readlink -f "${BASH_SOURCE[0]}")"
__dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
__real_dir="$(cd "$(dirname "${__real_file}")" && pwd)"
__caller_dir="$(pwd)"

# https://github.com/matejak/argbash
# https://argbash.io/
die()
{
    local _ret=${2:-1}
    echo "$1" >&2
    exit ${_ret}
}

print_help()
{
    printf 'Bash script "Test".\n'
    printf '\n'
    printf 'Usage: %s REQUIRED_PARAMETER_1 REQUIRED_PARAMETER_2 [OPTIONAL_PARAMETER_1] [OPTIONAL_PARAMETER_2] [REST]...\n' "$0"
    printf '\n'
    printf 'Additional message.'
}

if [ -z ${1:-} ]; then
    print_help
    exit 0
fi

first_argument=${1}

# https://medium.com/@Drew_Stokes/bash-argument-parsing-54f3b81a6a8f
eval set -- "${@:2}"

# https://ryanstutorials.net/bash-scripting-tutorial/bash-if-statements.php#case
case ${first_argument} in
    "first_case" | 1.2) # string OR int
        ;;
    *)
        die "Invalid first argument." 3 # die "Message" (int)exit_code
esac

# YOUR CODE