mirror of
https://github.com/kvz/bash3boilerplate.git
synced 2024-12-18 22:27:51 +00:00
f82bbe59b0
* better logging: support for multiple lines * renamed logging function from _fmt to __b3bp_log * adding example to show how multiline logging works the main idea is to be able to log e.g. the output of a command and b3bp taking care of splitting and prefixing every line. * simplified code, removed hacky space-at-EOL
279 lines
10 KiB
Bash
Executable File
279 lines
10 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 v2.0.0
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# Copyright (c) 2013 Kevin van Zonneveld and contributors
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# http://bash3boilerplate.sh/#authors
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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 ${VAR:-} to use an undefined VAR
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set -o nounset
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# Catch the error in case mysqldump fails (but gzip succeeds) in `mysqldump |gzip`
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set -o pipefail
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# Turn on traces, useful while debugging but commented out by default
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# set -o xtrace
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# Set magic variables for current file, directory, os, etc.
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__dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
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__file="${__dir}/$(basename "${BASH_SOURCE[0]}")"
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__base="$(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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local color_debug="\x1b[35m"
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local color_info="\x1b[32m"
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local color_notice="\x1b[34m"
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local color_warning="\x1b[33m"
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local color_error="\x1b[31m"
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local color_critical="\x1b[1;31m"
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local color_alert="\x1b[1;33;41m"
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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" ] || [[ "${TERM:-}" != "xterm"* ]] || [ -t 1 ]; then
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# Don't use colors on pipes or non-recognized terminals
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color=""; color_reset=""
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fi
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# all remaining arguments are to be printed
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local log_line=""
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while IFS=$'\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 () { $(__b3bp_log emergency "${@}") || true; 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 " ${__usage:-No usage available}" 1>&2
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echo "" 1>&2
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if [ -n "${__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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function cleanup_before_exit () {
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info "Cleaning up. Done"
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}
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trap cleanup_before_exit EXIT
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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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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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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 $arg_<flag> defaults
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while read __b3bp_tmp_line; do
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# fetch single character version of option string
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__b3bp_tmp_opt="$(echo "${__b3bp_tmp_line}" |awk '{print $1}' |sed -e 's#^-##')"
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# fetch long version if present
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__b3bp_tmp_long_opt="$(echo "${__b3bp_tmp_line}" |awk '/\-\-/ {print $2}' |sed -e 's#^--##')"
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__b3bp_tmp_long_opt_mangled="$(sed 's#-#_#g' <<< $__b3bp_tmp_long_opt)"
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# map long name back to short name
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__b3bp_tmp_varname="__b3bp_tmp_short_opt_${__b3bp_tmp_long_opt_mangled}"
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eval "${__b3bp_tmp_varname}=\"${__b3bp_tmp_opt}\""
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# check if option takes an argument
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__b3bp_tmp_varname="__b3bp_tmp_has_arg_${__b3bp_tmp_opt}"
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if ! echo "${__b3bp_tmp_line}" |egrep '\[.*\]' >/dev/null 2>&1; then
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__b3bp_tmp_init="0" # it's a flag. init with 0
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eval "${__b3bp_tmp_varname}=0"
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else
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__b3bp_tmp_opt="${__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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eval "${__b3bp_tmp_varname}=1"
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fi
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__b3bp_tmp_opts="${__b3bp_tmp_opts:-}${__b3bp_tmp_opt}"
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__b3bp_tmp_varname="arg_${__b3bp_tmp_opt:0:1}"
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if ! echo "${__b3bp_tmp_line}" |egrep '\. Default=' >/dev/null 2>&1; then
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eval "${__b3bp_tmp_varname}=\"${__b3bp_tmp_init}\""
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else
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__b3bp_tmp_match="$(echo "${__b3bp_tmp_line}" |sed 's#^.*Default=\(\)#\1#g')"
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eval "${__b3bp_tmp_varname}=\"${__b3bp_tmp_match}\""
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fi
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done <<< "${__usage:-}"
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# run getopts only if options were specified in __usage
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if [ -n "${__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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__b3bp_tmp_long_opt_mangled="$(sed 's#-#_#g' <<< $__b3bp_tmp_long_opt)"
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# Set opt to the short option corresponding to the long option
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eval "__b3bp_tmp_opt=\"\${__b3bp_tmp_short_opt_${__b3bp_tmp_long_opt_mangled}}\""
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OPTARG=${OPTARG#*=}
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else
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# --key value format
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# Map long name to short version of option
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__b3bp_tmp_long_opt_mangled="$(sed 's#-#_#g' <<< $OPTARG)"
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eval "__b3bp_tmp_opt=\"\${__b3bp_tmp_short_opt_${__b3bp_tmp_long_opt_mangled}}\""
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# Only assign OPTARG if option takes an argument
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eval "OPTARG=\"\${@:OPTIND:\${__b3bp_tmp_has_arg_${__b3bp_tmp_opt}}}\""
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# shift over the argument if argument is expected
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((OPTIND+=__b3bp_tmp_has_arg_${__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}" ] && [ "${__b3bp_tmp_default}" = "0" ]; then
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__b3bp_tmp_value="1"
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fi
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eval "${__b3bp_tmp_varname}=\"${__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 $((OPTIND-1))
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[ "${1:-}" = "--" ] && shift
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fi
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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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eval "unset ${__tmp_varname}"
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done
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unset __tmp_varname
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### Command-line argument switches (like -d for debugmode, -h for showing helppage)
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##############################################################################
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# debug mode
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if [ "${arg_d}" = "1" ]; then
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set -o xtrace
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LOG_LEVEL="7"
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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 ${0}"
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fi
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### Validation. Error out if the things required for your script are not present
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##############################################################################
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[ -z "${arg_f:-}" ] && help "Setting a filename with -f or --file is required"
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[ -z "${LOG_LEVEL:-}" ] && emergency "Cannot continue without LOG_LEVEL. "
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### Runtime
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##############################################################################
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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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