bash

• Bash website
• Bash Manual
• Advanced Bash-Scripting Guide
• How to increment a variable in bash?
• How can I do a "copy if changed" operation?

    #!/bin/bash
    set -eEu -o pipefail
    shopt -s failglob
    trap 'echo >&2 "${BASH_SOURCE:-$0}:${LINENO}: unknown error"' ERR