Style

Capitalization

Environment variables that are passed into and exported out of the script are written in UPPERCASE.
Local variables that are used within the script are written in lowercase.
Hence, no need to keep track of environment variables so you don't overwrite them.
No need to resort to LOCAL_FOO variable names either.

Invocation - which bash?

A surprising amount of systems do not have /bin/bash, or run a different Bash binary that's stored elsewhere on the system. This is especially the case with the BSDs, where I've ever only seen Bash in /usr/local/bin, MacOS, which ships with an ancient version of Bash that serious users will replace with Bash from Homebrew, and with NixOS, where /bin is empty by design.

This document will therefore standardize on

#!/usr/bin/env bash

in all examples.

Automatically deleting temporary files on exit

Use an event handler to automatically remove temporary files on exit.

#!/usr/bin/env bash

function cleanup(){
    trap - INT QUIT TERM EXIT
    rm -f "$tmpfile1"
    rm -f "$tmpfile1"
}
trap cleanup INT QUIT TERM EXIT

tmpfile1="$(mktemp)"
tmpfile1="$(mktemp)"

echo "$tmpfile1"
echo "$tmpfile2"

Trapping errors verbosely

#!/usr/bin/env bash
set -o errexit
function errorexit() {
        trap - ERR
        printf "Error on line %s\n" "$(caller)"
        exit 1
}
trap errorexit ERR

Establishing who you are

Finding the name of the script itself and the directory where it is stored.

#!/usr/bin/env bash
set -o errexit

me_path="$(readlink -f "$0")"
me_dir="$(dirname "${me_path}")"
me_base="$(basename "${me_path}")"

source "${me_dir}/config.conf"
printf "%s is up and running.\n" "${me_base}"