Shell scripts have value. Everything you do for real code should be done for non trivial shell scripts, even for a one-time script. That includes versioning, code reviews, continuous integration, static code analysis, and testing.

#!/usr/bin/env bash
set -euo pipefail
IFS=$'\n\t'

#/ Usage:
#/ Description:
#/ Examples:
#/ Options:
#/   --help: Display this help message
usage() { grep '^#/' "$0" | cut -c4- ; exit 0 ; }
expr "$*" : ".*--help" > /dev/null && usage

readonly LOG_FILE="/tmp/$(basename "$0").log"
info()    { echo "[INFO]    $@" | tee -a "$LOG_FILE" >&2 ; }
warning() { echo "[WARNING] $@" | tee -a "$LOG_FILE" >&2 ; }
error()   { echo "[ERROR]   $@" | tee -a "$LOG_FILE" >&2 ; }
fatal()   { echo "[FATAL]   $@" | tee -a "$LOG_FILE" >&2 ; exit 1 ; }

cleanup() {
    # Remove temporary files
    # Restart services
    # ...
}

if [[ "${BASH_SOURCE[0]}" = "$0" ]]; then
    trap cleanup EXIT
    # Script goes here
    # ...
fi