mirror of
https://github.com/kvz/bash3boilerplate.git
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2463cd6cc9
An example of use would be the passing in of multiple -v options in some utilities to increase verbosity.
394 lines
14 KiB
Bash
Executable File
394 lines
14 KiB
Bash
Executable File
#!/usr/bin/env bash
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# This file:
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#
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# - Demos BASH3 Boilerplate (change this for your script)
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#
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# Usage:
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#
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# LOG_LEVEL=7 ./main.sh -f /tmp/x -d (change this for your script)
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#
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# Based on a template by BASH3 Boilerplate v2.3.0
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# http://bash3boilerplate.sh/#authors
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#
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# The MIT License (MIT)
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# Copyright (c) 2013 Kevin van Zonneveld and contributors
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# You are not obligated to bundle the LICENSE file with your b3bp projects as long
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# as you leave these references intact in the header comments of your source files.
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# Exit on error. Append "|| true" if you expect an error.
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set -o errexit
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# Exit on error inside any functions or subshells.
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set -o errtrace
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# Do not allow use of undefined vars. Use ${VAR:-} to use an undefined VAR
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set -o nounset
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# Catch the error in case mysqldump fails (but gzip succeeds) in `mysqldump |gzip`
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set -o pipefail
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# Turn on traces, useful while debugging but commented out by default
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# set -o xtrace
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if [[ "${BASH_SOURCE[0]}" != "${0}" ]]; then
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__i_am_main_script="0" # false
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if [[ "${__usage+x}" ]]; then
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if [[ "${BASH_SOURCE[1]}" = "${0}" ]]; then
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__i_am_main_script="1" # true
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fi
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__b3bp_external_usage="true"
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__b3bp_tmp_source_idx=1
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fi
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else
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__i_am_main_script="1" # true
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[[ "${__usage+x}" ]] && unset -v __usage
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[[ "${__helptext+x}" ]] && unset -v __helptext
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fi
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# Set magic variables for current file, directory, os, etc.
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__dir="$(cd "$(dirname "${BASH_SOURCE[${__b3bp_tmp_source_idx:-0}]}")" && pwd)"
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__file="${__dir}/$(basename "${BASH_SOURCE[${__b3bp_tmp_source_idx:-0}]}")"
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__base="$(basename "${__file}" .sh)"
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# Define the environment variables (and their defaults) that this script depends on
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LOG_LEVEL="${LOG_LEVEL:-6}" # 7 = debug -> 0 = emergency
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NO_COLOR="${NO_COLOR:-}" # true = disable color. otherwise autodetected
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### Functions
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##############################################################################
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function __b3bp_log () {
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local log_level="${1}"
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shift
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# shellcheck disable=SC2034
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local color_debug="\\x1b[35m"
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# shellcheck disable=SC2034
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local color_info="\\x1b[32m"
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# shellcheck disable=SC2034
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local color_notice="\\x1b[34m"
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# shellcheck disable=SC2034
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local color_warning="\\x1b[33m"
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# shellcheck disable=SC2034
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local color_error="\\x1b[31m"
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# shellcheck disable=SC2034
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local color_critical="\\x1b[1;31m"
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# shellcheck disable=SC2034
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local color_alert="\\x1b[1;33;41m"
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# shellcheck disable=SC2034
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local color_emergency="\\x1b[1;4;5;33;41m"
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local colorvar="color_${log_level}"
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local color="${!colorvar:-${color_error}}"
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local color_reset="\\x1b[0m"
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if [[ "${NO_COLOR:-}" = "true" ]] || ( [[ "${TERM:-}" != "xterm"* ]] && [[ "${TERM:-}" != "screen"* ]] ) || [[ ! -t 2 ]]; then
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if [[ "${NO_COLOR:-}" != "false" ]]; then
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# Don't use colors on pipes or non-recognized terminals
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color=""; color_reset=""
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fi
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fi
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# all remaining arguments are to be printed
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local log_line=""
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while IFS=$'\n' read -r log_line; do
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echo -e "$(date -u +"%Y-%m-%d %H:%M:%S UTC") ${color}$(printf "[%9s]" "${log_level}")${color_reset} ${log_line}" 1>&2
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done <<< "${@:-}"
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}
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function emergency () { __b3bp_log emergency "${@}"; exit 1; }
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function alert () { [[ "${LOG_LEVEL:-0}" -ge 1 ]] && __b3bp_log alert "${@}"; true; }
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function critical () { [[ "${LOG_LEVEL:-0}" -ge 2 ]] && __b3bp_log critical "${@}"; true; }
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function error () { [[ "${LOG_LEVEL:-0}" -ge 3 ]] && __b3bp_log error "${@}"; true; }
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function warning () { [[ "${LOG_LEVEL:-0}" -ge 4 ]] && __b3bp_log warning "${@}"; true; }
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function notice () { [[ "${LOG_LEVEL:-0}" -ge 5 ]] && __b3bp_log notice "${@}"; true; }
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function info () { [[ "${LOG_LEVEL:-0}" -ge 6 ]] && __b3bp_log info "${@}"; true; }
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function debug () { [[ "${LOG_LEVEL:-0}" -ge 7 ]] && __b3bp_log debug "${@}"; true; }
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function help () {
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echo "" 1>&2
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echo " ${*}" 1>&2
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echo "" 1>&2
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echo " ${__usage:-No usage available}" 1>&2
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echo "" 1>&2
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if [[ "${__helptext:-}" ]]; then
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echo " ${__helptext}" 1>&2
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echo "" 1>&2
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fi
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exit 1
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}
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### Parse commandline options
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##############################################################################
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# Commandline options. This defines the usage page, and is used to parse cli
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# opts & defaults from. The parsing is unforgiving so be precise in your syntax
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# - A short option must be preset for every long option; but every short option
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# need not have a long option
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# - `--` is respected as the separator between options and arguments
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# - We do not bash-expand defaults, so setting '~/app' as a default will not resolve to ${HOME}.
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# you can use bash variables to work around this (so use ${HOME} instead)
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# shellcheck disable=SC2015
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[[ "${__usage+x}" ]] || read -r -d '' __usage <<-'EOF' || true # exits non-zero when EOF encountered
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-f --file [arg] Filename to process. Required.
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-t --temp [arg] Location of tempfile. Default="/tmp/bar"
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-v Enable verbose mode, print script as it is executed
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-d --debug Enables debug mode
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-h --help This page
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-n --no-color Disable color output
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-1 --one Do just one thing
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EOF
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# shellcheck disable=SC2015
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[[ "${__helptext+x}" ]] || read -r -d '' __helptext <<-'EOF' || true # exits non-zero when EOF encountered
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This is Bash3 Boilerplate's help text. Feel free to add any description of your
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program or elaborate more on command-line arguments. This section is not
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parsed and will be added as-is to the help.
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EOF
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# Translate usage string -> getopts arguments, and set $arg_<flag> defaults
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while read -r __b3bp_tmp_line; do
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if [[ "${__b3bp_tmp_line}" =~ ^- ]]; then
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# fetch single character version of option string
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__b3bp_tmp_opt="${__b3bp_tmp_line%% *}"
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__b3bp_tmp_opt="${__b3bp_tmp_opt:1}"
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# fetch long version if present
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__b3bp_tmp_long_opt=""
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if [[ "${__b3bp_tmp_line}" = *"--"* ]]; then
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__b3bp_tmp_long_opt="${__b3bp_tmp_line#*--}"
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__b3bp_tmp_long_opt="${__b3bp_tmp_long_opt%% *}"
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fi
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# map opt long name to+from opt short name
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printf -v "__b3bp_tmp_opt_long2short_${__b3bp_tmp_long_opt//-/_}" '%s' "${__b3bp_tmp_opt}"
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printf -v "__b3bp_tmp_opt_short2long_${__b3bp_tmp_opt}" '%s' "${__b3bp_tmp_long_opt//-/_}"
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# check if option takes an argument
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if [[ "${__b3bp_tmp_line}" =~ \[.*\] ]]; then
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__b3bp_tmp_opt="${__b3bp_tmp_opt}:" # add : if opt has arg
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__b3bp_tmp_init="" # it has an arg. init with ""
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printf -v "__b3bp_tmp_has_arg_${__b3bp_tmp_opt:0:1}" '%s' "1"
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elif [[ "${__b3bp_tmp_line}" =~ \{.*\} ]]; then
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__b3bp_tmp_opt="${__b3bp_tmp_opt}:" # add : if opt has arg
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__b3bp_tmp_init="" # it has an arg. init with ""
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# remember that this option requires an argument
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printf -v "__b3bp_tmp_has_arg_${__b3bp_tmp_opt:0:1}" '%s' "2"
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else
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__b3bp_tmp_init="0" # it's a flag. init with 0
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printf -v "__b3bp_tmp_has_arg_${__b3bp_tmp_opt:0:1}" '%s' "0"
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fi
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__b3bp_tmp_opts="${__b3bp_tmp_opts:-}${__b3bp_tmp_opt}"
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fi
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[[ "${__b3bp_tmp_opt:-}" ]] || continue
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if [[ "${__b3bp_tmp_line}" =~ ^Default= ]] || [[ "${__b3bp_tmp_line}" =~ \.\ *Default= ]]; then
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# ignore default value if option does not have an argument
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__b3bp_tmp_varname="__b3bp_tmp_has_arg_${__b3bp_tmp_opt:0:1}"
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if [[ "${!__b3bp_tmp_varname}" != "0" ]]; then
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__b3bp_tmp_init="${__b3bp_tmp_line##*Default=}"
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__b3bp_tmp_re='^"(.*)"$'
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if [[ "${__b3bp_tmp_init}" =~ ${__b3bp_tmp_re} ]]; then
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__b3bp_tmp_init="${BASH_REMATCH[1]}"
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else
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__b3bp_tmp_re="^'(.*)'$"
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if [[ "${__b3bp_tmp_init}" =~ ${__b3bp_tmp_re} ]]; then
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__b3bp_tmp_init="${BASH_REMATCH[1]}"
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fi
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fi
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fi
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fi
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if [[ "${__b3bp_tmp_line}" =~ ^Required\. ]] || [[ "${__b3bp_tmp_line}" =~ \.\ *Required\. ]]; then
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# remember that this option requires an argument
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printf -v "__b3bp_tmp_has_arg_${__b3bp_tmp_opt:0:1}" '%s' "2"
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fi
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printf -v "arg_${__b3bp_tmp_opt:0:1}" '%s' "${__b3bp_tmp_init}"
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done <<< "${__usage:-}"
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# run getopts only if options were specified in __usage
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if [[ "${__b3bp_tmp_opts:-}" ]]; then
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# Allow long options like --this
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__b3bp_tmp_opts="${__b3bp_tmp_opts}-:"
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# Reset in case getopts has been used previously in the shell.
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OPTIND=1
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# start parsing command line
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set +o nounset # unexpected arguments will cause unbound variables
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# to be dereferenced
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# Overwrite $arg_<flag> defaults with the actual CLI options
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while getopts "${__b3bp_tmp_opts}" __b3bp_tmp_opt; do
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[[ "${__b3bp_tmp_opt}" = "?" ]] && help "Invalid use of script: ${*} "
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if [[ "${__b3bp_tmp_opt}" = "-" ]]; then
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# OPTARG is long-option-name or long-option=value
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if [[ "${OPTARG}" =~ .*=.* ]]; then
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# --key=value format
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__b3bp_tmp_long_opt=${OPTARG/=*/}
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# Set opt to the short option corresponding to the long option
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__b3bp_tmp_varname="__b3bp_tmp_opt_long2short_${__b3bp_tmp_long_opt//-/_}"
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printf -v "__b3bp_tmp_opt" '%s' "${!__b3bp_tmp_varname}"
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OPTARG=${OPTARG#*=}
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else
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# --key value format
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# Map long name to short version of option
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__b3bp_tmp_varname="__b3bp_tmp_opt_long2short_${OPTARG//-/_}"
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printf -v "__b3bp_tmp_opt" '%s' "${!__b3bp_tmp_varname}"
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# Only assign OPTARG if option takes an argument
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__b3bp_tmp_varname="__b3bp_tmp_has_arg_${__b3bp_tmp_opt}"
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printf -v "OPTARG" '%s' "${@:OPTIND:${!__b3bp_tmp_varname}}"
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# shift over the argument if argument is expected
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((OPTIND+=__b3bp_tmp_has_arg_${__b3bp_tmp_opt}))
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fi
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# we have set opt/OPTARG to the short value and the argument as OPTARG if it exists
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fi
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__b3bp_tmp_varname="arg_${__b3bp_tmp_opt:0:1}"
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__b3bp_tmp_default="${!__b3bp_tmp_varname}"
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__b3bp_tmp_value="${OPTARG}"
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if [[ -z "${OPTARG}" ]]; then
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__b3bp_tmp_value=$((__b3bp_tmp_default + 1))
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fi
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printf -v "${__b3bp_tmp_varname}" '%s' "${__b3bp_tmp_value}"
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debug "cli arg ${__b3bp_tmp_varname} = (${__b3bp_tmp_default}) -> ${!__b3bp_tmp_varname}"
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done
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set -o nounset # no more unbound variable references expected
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shift $((OPTIND-1))
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if [[ "${1:-}" = "--" ]] ; then
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shift
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fi
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fi
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### Automatic validation of required option arguments
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##############################################################################
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for __b3bp_tmp_varname in ${!__b3bp_tmp_has_arg_*}; do
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# validate only options which required an argument
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[[ "${!__b3bp_tmp_varname}" = "2" ]] || continue
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__b3bp_tmp_opt_short="${__b3bp_tmp_varname##*_}"
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__b3bp_tmp_varname="arg_${__b3bp_tmp_opt_short}"
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[[ "${!__b3bp_tmp_varname}" ]] && continue
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__b3bp_tmp_varname="__b3bp_tmp_opt_short2long_${__b3bp_tmp_opt_short}"
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printf -v "__b3bp_tmp_opt_long" '%s' "${!__b3bp_tmp_varname}"
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[[ "${__b3bp_tmp_opt_long:-}" ]] && __b3bp_tmp_opt_long=" (--${__b3bp_tmp_opt_long//_/-})"
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help "Option -${__b3bp_tmp_opt_short}${__b3bp_tmp_opt_long:-} requires an argument"
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done
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### Cleanup Environment variables
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##############################################################################
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for __tmp_varname in ${!__b3bp_tmp_*}; do
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unset -v "${__tmp_varname}"
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done
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unset -v __tmp_varname
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### Externally supplied __usage. Nothing else to do here
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##############################################################################
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if [[ "${__b3bp_external_usage:-}" = "true" ]]; then
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unset -v __b3bp_external_usage
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return
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fi
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### Signal trapping and backtracing
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##############################################################################
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function __b3bp_cleanup_before_exit () {
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info "Cleaning up. Done"
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}
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trap __b3bp_cleanup_before_exit EXIT
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# requires `set -o errtrace`
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__b3bp_err_report() {
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local error_code
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error_code=${?}
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error "Error in ${__file} in function ${1} on line ${2}"
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exit ${error_code}
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}
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# Uncomment the following line for always providing an error backtrace
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# trap '__b3bp_err_report "${FUNCNAME:-.}" ${LINENO}' ERR
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### Command-line argument switches (like -d for debugmode, -h for showing helppage)
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##############################################################################
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# debug mode
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if [[ "${arg_d:?}" = "1" ]]; then
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set -o xtrace
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LOG_LEVEL="7"
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# Enable error backtracing
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trap '__b3bp_err_report "${FUNCNAME:-.}" ${LINENO}' ERR
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fi
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# verbose mode
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if [[ "${arg_v:?}" = "1" ]]; then
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set -o verbose
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fi
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# no color mode
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if [[ "${arg_n:?}" = "1" ]]; then
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NO_COLOR="true"
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fi
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# help mode
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if [[ "${arg_h:?}" = "1" ]]; then
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# Help exists with code 1
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help "Help using ${0}"
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fi
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### Validation. Error out if the things required for your script are not present
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##############################################################################
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[[ "${arg_f:-}" ]] || help "Setting a filename with -f or --file is required"
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[[ "${LOG_LEVEL:-}" ]] || emergency "Cannot continue without LOG_LEVEL. "
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### Runtime
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##############################################################################
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info "__i_am_main_script: ${__i_am_main_script}"
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info "__file: ${__file}"
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info "__dir: ${__dir}"
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info "__base: ${__base}"
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info "OSTYPE: ${OSTYPE}"
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info "arg_f: ${arg_f}"
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info "arg_d: ${arg_d}"
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info "arg_v: ${arg_v}"
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info "arg_h: ${arg_h}"
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info "$(echo -e "multiple lines example - line #1\\nmultiple lines example - line #2\\nimagine logging the output of 'ls -al /path/'")"
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# All of these go to STDERR, so you can use STDOUT for piping machine readable information to other software
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debug "Info useful to developers for debugging the application, not useful during operations."
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info "Normal operational messages - may be harvested for reporting, measuring throughput, etc. - no action required."
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notice "Events that are unusual but not error conditions - might be summarized in an email to developers or admins to spot potential problems - no immediate action required."
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warning "Warning messages, not an error, but indication that an error will occur if action is not taken, e.g. file system 85% full - each item must be resolved within a given time. This is a debug message"
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error "Non-urgent failures, these should be relayed to developers or admins; each item must be resolved within a given time."
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critical "Should be corrected immediately, but indicates failure in a primary system, an example is a loss of a backup ISP connection."
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alert "Should be corrected immediately, therefore notify staff who can fix the problem. An example would be the loss of a primary ISP connection."
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emergency "A \"panic\" condition usually affecting multiple apps/servers/sites. At this level it would usually notify all tech staff on call."
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