fix(bkgpslog):Check -e, -r, -R option combinations; update usage

[EVA-2020-02.git] / exec / bkgpslog

#!/bin/bash

# Desc: Records gps data until midnight
# Author: Steven Baltakatei Sandoval; License: GPLv3+
# Usage: bkgpslog -o [output dir]

#==BEGIN Define script parameters==
## Logging Behavior parameters
BUFFER_TTL="300"; # time between file writes
SCRIPT_TTL="day"; # (day|hour)
#### TZ="UTC"; export TZ; # Default time zone; overridden by '--time-zone=[str]' option
DIR_TMP_DEFAULT="/dev/shm"; # Default parent of working directory

SCRIPT_TIME_START=$(date +%Y%m%dT%H%M%S.%N);
PATH="$HOME/.local/bin:$PATH";   # Add "$(systemd-path user-binaries)" path in case apps saved there
SCRIPT_HOSTNAME=$(hostname);     # Save hostname of system running this script.
SCRIPT_VERSION="0.3.9";          # Define version of script.
SCRIPT_NAME="bkgpslog";          # Define basename of script file.
SCRIPT_URL="https://gitlab.com/baltakatei/ninfacyzga-01"; # Define wesite hosting this script.
AGE_VERSION="1.0.0-beta2";       # Define version of age (encryption program)
AGE_URL="https://github.com/FiloSottile/age/releases/tag/v1.0.0-beta2"; # Define website hosting age.

declare -Ag appRollCall # Associative array for storing app status
declare -Ag fileRollCall # Associative array for storing file status
declare -Ag dirRollCall # Associative array for storing dir status
declare -a argRecPubKeys # for processArguments function

## Initialize variables
OPTION_VERBOSE=""; OPTION_ENCRYPT=""; OPTION_COMPRESS=""; OPTION_TMPDIR="";

#===BEGIN Declare local script functions===
checkapp() {
    # Desc: If arg is a command, save result in assoc array 'appRollCall'
    # Usage: checkapp arg1 arg2 arg3 ...
    # Input: global assoc. array 'appRollCall'
    # Output: adds/updates key(value) to global assoc array 'appRollCall'
    local returnState    
    #echo "DEBUG:$(date +%S.%N)..Starting checkapp function."
    #echo "DEBUG:args: $@"
    #echo "DEBUG:returnState:$returnState"

    #===Process Args===
    for arg in "$@"; do
	#echo "DEBUG:processing arg:$arg"
	if command -v "$arg" 1>/dev/null 2>&1; then # Check if arg is a valid command
	    appRollCall[$arg]="true";
	    #echo "DEBUG:appRollCall[$arg]:"${appRollCall[$arg]}
	    if ! [ "$returnState" = "false" ]; then returnState="true"; fi
	else
	    appRollCall[$arg]="false"; returnState="false";
	fi
    done
    
    #for key in "${!appRollCall[@]}"; do echo "DEBUG:$key => ${appRollCall[$key]}"; done
    #echo "DEBUG:evaluating returnstate. returnState:"$returnState

    #===Determine function return code===
    if [ "$returnState" = "true" ]; then
	#echo "DEBUG:checkapp returns true for $arg";
	return 0;
    else
	#echo "DEBUG:checkapp returns false for $arg";
	return 1;
    fi
} # Check that app exists
checkfile() {
    # Desc: If arg is a file path, save result in assoc array 'fileRollCall'
    # Usage: checkfile arg1 arg2 arg3 ...
    # Input: global assoc. array 'fileRollCall'
    # Output: adds/updates key(value) to global assoc array 'fileRollCall';
    # Output: returns 0 if app found, 1 otherwise
    local returnState

    #===Process Args===
    for arg in "$@"; do
	#echo "DEBUG:processing arg:$arg"
	if [ -f "$arg" ]; then
	    fileRollCall["$arg"]="true";
	    #echo "DEBUG:fileRollCall[\"$arg\"]:"${fileRollCall["$arg"]}
	    if ! [ "$returnState" = "false" ]; then returnState="true"; fi
	else
	    fileRollCall["$arg"]="false"; returnState="false";
	fi
    done

    #for key in "${!fileRollCall[@]}"; do echo "DEBUG:fileRollCall key [$key] is:${fileRollCall[$key]}"; done
    #echo "DEBUG:evaluating returnstate. returnState:"$returnState
    
    #===Determine function return code===
    if [ "$returnState" = "true" ]; then
	#echo "DEBUG:checkapp returns true for $arg";
	return 0;
    else
	#echo "DEBUG:checkapp returns false for $arg";
	return 1;
    fi
} # Check that file exists
checkdir() {
    # Desc: If arg is a dir path, save result in assoc array 'dirRollCall'
    # Usage: checkdir arg1 arg2 arg3 ...
    # Input: global assoc. array 'dirRollCall'
    # Output: adds/updates key(value) to global assoc array 'dirRollCall';
    # Output: returns 0 if app found, 1 otherwise
    local returnState

    #===Process Args===
    for arg in "$@"; do
	#echo "DEBUG:processing arg:$arg"
	if [ -d "$arg" ]; then
	    dirRollCall["$arg"]="true";
	    #echo "DEBUG:dirRollCall[\"$arg\"]:"${dirRollCall["$arg"]}
	    if ! [ "$returnState" = "false" ]; then returnState="true"; fi
	elif [ "$arg" = "" ]; then
	    dirRollCall["$arg"]="false"; returnState="false";
	else
	    returnState="false";
	fi
    done

    #for key in "${!dirRollCall[@]}"; do echo "DEBUG:dirRollCall key [$key] is:${dirRollCall[$key]}"; done
    #echo "DEBUG:evaluating returnstate. returnState:"$returnState
    
    #===Determine function return code===
    if [ "$returnState" = "true" ]; then
	#echo "DEBUG:checkapp returns true for $arg";
	return 0;
    else
	#echo "DEBUG:checkapp returns false for $arg";
	return 1;
    fi
} # Check that dir exists

# Yell, Die, Try Three-Fingered Claw technique
# Ref/Attrib: https://stackoverflow.com/a/25515370
yell() { echo "$0: $*" >&2; }
die() { yell "$*"; exit 111; }
try() { "$@" || die "cannot $*"; }

echoerr() {
    echo "$@" 1>&2; # Define stderr echo function.
} # Define stderr message function.
showUsage() {
    echoerr "USAGE:"
    echoerr "    bkgpslog [ options ]"
    echoerr
    echoerr "OPTIONS:"
    echoerr "    -h, --help"
    echoerr "            Display help information."
    echoerr "    --version"
    echoerr "            Display script version."
    echoerr "    -v, --verbose"
    echoerr "            Display debugging info."
    echoerr "    -e, --encrypt"
    echoerr "            Encrypt output."
    echoerr "    -r, --recipient [ pubkey string ]"
    echoerr "            Specify recipient. May be age or ssh pubkey."
    echoerr "            See https://github.com/FiloSottile/age"
    echoerr "    -o, --output [ directory ]"
    echoerr "            Specify output directory to save logs."
    echoerr "    -c, --compress"
    echoerr "            Compress output with gzip (before encryption if enabled)."
    echoerr "    -z, --time-zone"
    echoerr "            Specify time zone. (ex: \"America/New_York\")"
    echoerr "    -t, --temp-dir"
    echoerr "            Specify parent directory for temporary working directory."
    echoerr "            Default: \"/dev/shm\""
    echoerr "    -R, --recipient-dir"
    echoerr "            Specify directory containing files whose first lines are"
    echoerr "            to be interpreted as pubkey strings (see \'-r\' option)."
    echoerr
    echoerr "EXAMPLE: (bash script lines)"
    echoerr "/bin/bash bkgpslog -v -e -c \\"
    echoerr "-z \"UTC\" -t \"/dev/shm\" \\"
    echoerr "-r age1mrmfnwhtlprn4jquex0ukmwcm7y2nxlphuzgsgv8ew2k9mewy3rs8u7su5 \\"
    echoerr "-r age1ala848kqrvxc88rzaauc6vc5v0fqrvef9dxyk79m0vjea3hagclswu0lgq \\"
    echoerr "-o ~/Sync/Location"
} # Display information on how to use this script.
showVersion() {
    echoerr "$SCRIPT_VERSION"
} # Display script version.
vbm() {
    # Usage: vbm "DEBUG:verbose message here"
    # Description: Prints verbose message ("vbm") to stderr if OPTION_VERBOSE is set to "true".
    # Input:
    #   - OPTION_VERBOSE  variable set by processArguments function. (ex: "true", "false")
    #   - "$@"            positional arguments fed to this function.
    # Output: stderr
    # Script function dependencies: echoerr
    # External function dependencies: echo
    # Last modified: 2020-04-11T23:57Z
    # Last modified by: Steven Baltakatei Sandoval
    # License: GPLv3+
    # Ref./Attrib:

    if [ "$OPTION_VERBOSE" = "true" ]; then
	FUNCTION_TIME=$(date --iso-8601=ns); # Save current time in nano seconds.
	echoerr "[$FUNCTION_TIME] ""$*"; # Display argument text.
    fi

    # End function
    return 0; # Function finished.
} # Verbose message display function.
processArguments() {
    while [ ! $# -eq 0 ]; do   # While number of arguments ($#) is not (!) equal to (-eq) zero (0).
	#echoerr "DEBUG:Starting processArguments while loop."
	#echoerr "DEBUG:Provided arguments are:""$*"
	case "$1" in
	    -h | --help) showUsage; exit 1;; # Display usage.
	    --version) showVersion; exit 1;; # Show version
	    -v | --verbose) OPTION_VERBOSE="true"; vbm "DEBUG:Verbose mode enabled.";; # Enable verbose mode.
	    -o | --output) if [ -d "$2" ]; then DIR_OUT="$2"; vbm "DEBUG:DIR_OUT:$DIR_OUT"; shift; fi ;; # Define output directory.
	    -e | --encrypt) OPTION_ENCRYPT="true"; vbm "DEBUG:Encrypted output mode enabled.";; # Enable encryption
	    -r | --recipient) OPTION_RECIPIENTS="true"; argRecPubKeys+=("$2"); vbm "STATUS:pubkey added:""$2"; shift;; # Add recipients
	    -c | --compress) OPTION_COMPRESS="true"; vbm "DEBUG:Compressed output mode enabled.";; # Enable compression
	    -z | --time-zone) try setTimeZoneEV "$2"; shift;; # Set timestamp timezone
	    -t | --temp-dir) OPTION_TMPDIR="true" && argTmpDirPriority="$2"; shift;; # Set time zone
	    -R | --recipient-dir) OPTION_RECIPIENTS="true"; OPTION_RECDIR="true" && argRecDir="$2"; shift;; # Add recipient watch dir
	    *) echoerr "ERROR: Unrecognized argument: $1"; echoerr "STATUS:All arguments:$*"; exit 1;; # Handle unrecognized options.
	esac
	shift
    done
} # Argument Processing
setTimeZoneEV(){
    # Desc: Set time zone environment variable TZ
    # Usage: setTimeZoneEV arg1
    # Input: arg1: 'date'-compatible timezone string (ex: "America/New_York")
    #        TZDIR env var (optional; default: "/usr/share/zoneinfo")
    # Output: exports TZ
    #         exit code 0 on success
    #         exit code 1 on incorrect number of arguments
    #         exit code 2 if unable to validate arg1
    # Depends: yell, printenv, bash 5
    # Tested on: Debian 10
    ARG1="$1"
    local tzDir returnState
    if ! [[ $# -eq 1 ]]; then
	yell "ERROR:Invalid argument count.";
	return 1;
    fi

    # Read TZDIR env var if available
    if printenv TZDIR 1>/dev/null 2>&1; then
	tzDir="$(printenv TZDIR)";
    else
	tzDir="/usr/share/zoneinfo";
    fi
    
    # Validate TZ string
    if ! [[ -f "$tzDir"/"$ARG1" ]]; then
	yell "ERROR:Invalid time zone argument.";
	return 2;
    else
    # Export ARG1 as TZ environment variable
	TZ="$ARG1" && export TZ && returnState="true";
    fi

    # Determine function return code
    if [ "$returnState" = "true" ]; then
	return 0;
    fi
} # Exports TZ environment variable
timeUntilNextDay(){
    # Desc: Report seconds until next day.
    # Version: 1.0.0
    # Output: stdout: integer seconds until next day
    # Output: exit code 0 if stdout > 0; 1 if stdout = 0; 2 if stdout < 0
    # Usage: timeUntilNextDay
    # Usage: if ! myTTL="$(timeUntilNextDay)"; then yell "ERROR in if statement"; exit 1; fi
    # Depends: date 8, echo 8, yell, try
    
    local returnState TIME_CURRENT TIME_NEXT_DAY SECONDS_UNTIL_NEXT_DAY

    TIME_CURRENT="$(date --iso-8601=seconds)" ; # Produce `date`-parsable current timestamp with resolution of 1 second.
    TIME_NEXT_DAY="$(date -d "$TIME_CURRENT next day" --iso-8601=date)"; # Produce timestamp of beginning of tomorrow with resolution of 1 second.
    SECONDS_UNTIL_NEXT_DAY="$(( $(date +%s -d "$TIME_NEXT_DAY") - $(date +%s -d "$TIME_CURRENT") ))" ; # Calculate seconds until closest future midnight (res. 1 second).
    if [[ "$SECONDS_UNTIL_NEXT_DAY" -gt 0 ]]; then
	returnState="true";
    elif [[ "$SECONDS_UNTIL_NEXT_DAY" -eq 0 ]]; then
	returnState="warning_zero";
	yell "WARNING:Reported time until next day exactly zero.";
    elif [[ "$SECONDS_UNTIL_NEXT_DAY" -lt 0 ]]; then
	returnState="warning_negative";
	yell "WARNING:Reported time until next day is negative.";
    fi

    try echo "$SECONDS_UNTIL_NEXT_DAY"; # Report
    
    # Determine function return code
    if [[ "$returnState" = "true" ]]; then
	return 0;
    elif [[ "$returnState" = "warning_zero" ]]; then
	return 1;
    elif [[ "$returnState" = "warning_negative" ]]; then
	return 2;
    fi
} # Report seconds until next day
timeUntilNextHour(){
    # Desc: Report seconds until next hour
    # Version 1.0.0
    # Output: stdout: integer seconds until next hour
    # Output: exit code 0 if stdout > 0; 1 if stdout = 0; 2 if stdout < 0
    # Usage: timeUntilNextHour
    # Usage: if ! myTTL="$(timeUntilNextHour)"; then yell "ERROR in if statement"; exit 1; fi
    
    local returnState TIME_CURRENT TIME_NEXT_HOUR SECONDS_UNTIL_NEXT_HOUR
    TIME_CURRENT="$(date --iso-8601=seconds)"; # Produce `date`-parsable current timestamp with resolution of 1 second.
    TIME_NEXT_HOUR="$(date -d "$TIME_CURRENT next hour" --iso-8601=hours)"; # Produce `date`-parsable current time stamp with resolution of 1 second.
    SECONDS_UNTIL_NEXT_HOUR="$(( $(date +%s -d "$TIME_NEXT_HOUR") - $(date +%s -d "$TIME_CURRENT") ))"; # Calculate seconds until next hour (res. 1 second).
    if [[ "$SECONDS_UNTIL_NEXT_HOUR" -gt 0 ]]; then
	returnState="true";
    elif [[ "$SECONDS_UNTIL_NEXT_HOUR" -eq 0 ]]; then
	returnState="warning_zero";
	yell "WARNING:Reported time until next hour exactly zero.";
    elif [[ "$SECONDS_UNTIL_NEXT_HOUR" -lt 0 ]]; then
	returnState="warning_negative";
	yell "WARNING:Reported time until next hour is negative.";
    fi

    try echo "$SECONDS_UNTIL_NEXT_HOUR"; # Report
    
    # Determine function return code
    if [[ "$returnState" = "true" ]]; then
	return 0;
    elif [[ "$returnState" = "warning_zero" ]]; then
	return 1;
    elif [[ "$returnState" = "warning_negative" ]]; then
	return 2;
    fi
} # Report seconds until next hour
dateTimeShort(){
    # Desc: Timestamp without separators (YYYYmmddTHHMMSS+zzzz)
    # Usage: dateTimeShort ([str date])
    # Version 1.1.0
    # Input: arg1: 'date'-parsable timestamp string (optional)
    # Output: stdout: timestamp (ISO-8601, no separators)
    # Depends: yell
    local TIME_CURRENT TIME_CURRENT_SHORT

    argTime="$1";
    # Get Current Time
    TIME_CURRENT="$(date --iso-8601=seconds)" ; # Produce `date`-parsable current timestamp with resolution of 1 second.
    # Decide to parse current or supplied date
    ## Check if time argument empty
    if [[ -z "$argTime" ]]; then
	## T: Time argument empty, use current time
	TIME_INPUT="$TIME_CURRENT";
    else
	## F: Time argument exists, validate time
	if date --date="$argTime" 1>/dev/null 2>&1; then
	    ### T: Time argument is valid; use it
	    TIME_INPUT="$argTime";
	else
	    ### F: Time argument not valid; exit
	    yell "ERROR:Invalid time argument supplied. Exiting."; exit 1;
	fi
    fi
    # Construct and deliver separator-les date string
    TIME_CURRENT_SHORT="$(date -d "$TIME_INPUT" +%Y%m%dT%H%M%S%z)";
    echo "$TIME_CURRENT_SHORT";
} # Get YYYYmmddTHHMMSS±zzzz
dateShort(){
    # Desc: Date without separators (YYYYmmdd)
    # Usage: dateShort ([str date])
    # Version: 1.1.0
    # Input: arg1: 'date'-parsable timestamp string (optional)
    # Output: stdout: date (ISO-8601, no separators)
    # Depends: yell
    local TIME_CURRENT DATE_CURRENT_SHORT

    argTime="$1";
    # Get Current Time
    TIME_CURRENT="$(date --iso-8601=seconds)" ; # Produce `date`-parsable current timestamp with resolution of 1 second.
    # Decide to parse current or supplied date
    ## Check if time argument empty
    if [[ -z "$argTime" ]]; then
	## T: Time argument empty, use current time
	TIME_INPUT="$TIME_CURRENT";
    else
	## F: Time argument exists, validate time
	if date --date="$argTime" 1>/dev/null 2>&1; then
	    ### T: Time argument is valid; use it
	    TIME_INPUT="$argTime";
	else
	    ### F: Time argument not valid; exit
	    yell "ERROR:Invalid time argument supplied. Exiting."; exit 1;
	fi
    fi
    # Construct and deliver separator-les date string    
    DATE_CURRENT_SHORT="$(date -d "$TIME_INPUT" +%Y%m%d)"; # Produce separator-less current date with resolution 1 day.
    echo "$DATE_CURRENT_SHORT";
} # Get YYYYmmdd
timeDuration(){
    # Desc: Given seconds, output ISO-8601 duration string
    # Ref/Attrib: ISO-8601:2004(E), §4.4.4.2 Representations of time intervals by duration and context information
    # Note: "1 month" ("P1M") is assumed to be "30 days" (see ISO-8601:2004(E), §2.2.1.2)
    # Usage: timeDuration [1:seconds] ([2:precision])
    # Version: 1.0.3
    # Input: arg1: seconds as base 10 integer >= 0  (ex: 3601)
    #        arg2: precision level (optional; default=2)
    # Output: stdout: ISO-8601 duration string (ex: "P1H1S", "P2Y10M15DT10H30M20S")
    #         exit code 0: success
    #         exit code 1: error_input
    #         exit code 2: error_unknown
    # Example: 'timeDuration 111111 3' yields 'P1DT6H51M'
    # Depends: date 8 (gnucoreutils), yell, 
    local returnState argSeconds argPrecision remainder precision witherPrecision
    local fullYears fullMonths fullDays fullHours fullMinutes fullSeconds
    local displayYears displayMonths displayDays displayHours displayMinutes displaySeconds
    local hasYears hasMonths hasDays hasHours hasMinutes hasSeconds
    
    argSeconds="$1"; # read arg1 (seconds)
    argPrecision="$2"; # read arg2 (precision)
    precision=2; # set default precision

    # Check that between one and two arguments is supplied
    if ! { [[ $# -ge 1 ]] && [[ $# -le 2 ]]; }; then
	yell "ERROR:Invalid number of arguments:$# . Exiting.";
	returnState="error_input"; fi

    # Check that argSeconds provided
    if [[ $# -ge 1 ]]; then
	## Check that argSeconds is a positive integer
	if [[ "$argSeconds" =~ ^[[:digit:]]+$ ]]; then
   	    :
	else
	    yell "ERROR:argSeconds not a digit.";
	    returnState="error_input";
	fi
    else
	yell "ERROR:No argument provided. Exiting.";
	exit 1;
    fi

    # Consider whether argPrecision was provided
    if  [[ $# -eq 2 ]]; then
	# Check that argPrecision is a positive integer
	if [[ "$argPrecision" =~ ^[[:digit:]]+$ ]] && [[ "$argPrecision" -gt 0 ]]; then
	precision="$argPrecision";
	else
	    yell "ERROR:argPrecision not a positive integer. (is $argPrecision ). Leaving early.";
	    returnState="error_input";
	fi;
    else
	:
    fi;
    
    remainder="$argSeconds" ; # seconds
    ## Calculate full years Y, update remainder
    fullYears=$(( remainder / (365*24*60*60) ));
    remainder=$(( remainder - (fullYears*365*24*60*60) ));
    ## Calculate full months M, update remainder
    fullMonths=$(( remainder / (30*24*60*60) ));
    remainder=$(( remainder - (fullMonths*30*24*60*60) ));
    ## Calculate full days D, update remainder
    fullDays=$(( remainder / (24*60*60) ));
    remainder=$(( remainder - (fullDays*24*60*60) ));
    ## Calculate full hours H, update remainder
    fullHours=$(( remainder / (60*60) ));
    remainder=$(( remainder - (fullHours*60*60) ));
    ## Calculate full minutes M, update remainder
    fullMinutes=$(( remainder / (60) ));
    remainder=$(( remainder - (fullMinutes*60) ));
    ## Calculate full seconds S, update remainder
    fullSeconds=$(( remainder / (1) ));
    remainder=$(( remainder - (remainder*1) ));
    ## Check which fields filled
    if [[ $fullYears -gt 0 ]]; then hasYears="true"; else hasYears="false"; fi
    if [[ $fullMonths -gt 0 ]]; then hasMonths="true"; else hasMonths="false"; fi
    if [[ $fullDays -gt 0 ]]; then hasDays="true"; else hasDays="false"; fi
    if [[ $fullHours -gt 0 ]]; then hasHours="true"; else hasHours="false"; fi
    if [[ $fullMinutes -gt 0 ]]; then hasMinutes="true"; else hasMinutes="false"; fi
    if [[ $fullSeconds -gt 0 ]]; then hasSeconds="true"; else hasSeconds="false"; fi
    
    ## Determine which fields to display (see ISO-8601:2004 §4.4.3.2)
    witherPrecision="false"
    
    ### Years
    if $hasYears && [[ $precision -gt 0 ]]; then
	displayYears="true";
	witherPrecision="true";
    else
	displayYears="false";
    fi;
    if $witherPrecision; then ((precision--)); fi;
    
    ### Months
    if $hasMonths && [[ $precision -gt 0 ]]; then
	displayMonths="true";
	witherPrecision="true";
    else
	displayMonths="false";
    fi;
    if $witherPrecision && [[ $precision -gt 0 ]]; then
	displayMonths="true";
    fi;
    if $witherPrecision; then ((precision--)); fi;

    ### Days
    if $hasDays && [[ $precision -gt 0 ]]; then
	displayDays="true";
	witherPrecision="true";
    else
	displayDays="false";
    fi;
    if $witherPrecision && [[ $precision -gt 0 ]]; then
	displayDays="true";
    fi;
    if $witherPrecision; then ((precision--)); fi;

    ### Hours
    if $hasHours && [[ $precision -gt 0 ]]; then
	displayHours="true";
	witherPrecision="true";
    else
	displayHours="false";
    fi;
    if $witherPrecision && [[ $precision -gt 0 ]]; then
	displayHours="true";
    fi;
    if $witherPrecision; then ((precision--)); fi;

    ### Minutes
    if $hasMinutes && [[ $precision -gt 0 ]]; then
	displayMinutes="true";
	witherPrecision="true";
    else
	displayMinutes="false";
    fi;
    if $witherPrecision && [[ $precision -gt 0 ]]; then
	displayMinutes="true";
    fi;
    if $witherPrecision; then ((precision--)); fi;

    ### Seconds

    if $hasSeconds && [[ $precision -gt 0 ]]; then
	displaySeconds="true";
	witherPrecision="true";
    else
	displaySeconds="false";
    fi;
    if $witherPrecision && [[ $precision -gt 0 ]]; then
	displaySeconds="true";
    fi;
    if $witherPrecision; then ((precision--)); fi;

    ## Determine whether or not the "T" separator is needed to separate date and time elements
    if ( $displayHours || $displayMinutes || $displaySeconds); then
	displayDateTime="true"; else displayDateTime="false"; fi
    
    ## Construct duration output string
    OUTPUT="P"
    if $displayYears; then
	OUTPUT=$OUTPUT$fullYears"Y"; fi
    if $displayMonths; then
	OUTPUT=$OUTPUT$fullMonths"M"; fi
    if $displayDays; then
	OUTPUT=$OUTPUT$fullDays"D"; fi
    if $displayDateTime; then
	OUTPUT=$OUTPUT"T"; fi
    if $displayHours; then
	OUTPUT=$OUTPUT$fullHours"H"; fi
    if $displayMinutes; then
	OUTPUT=$OUTPUT$fullMinutes"M"; fi
    if $displaySeconds; then
	OUTPUT=$OUTPUT$fullSeconds"S"; fi

    ## Output duration string to stdout
    echo "$OUTPUT" && returnState="true";

    #===Determine function return code===
    if [ "$returnState" = "true" ]; then
	return 0;
    elif [ "$returnState" = "error_input" ]; then
	yell "ERROR:input";
	return 1;
    else
	yell "ERROR:Unknown";
	return 2;
    fi

} # Get duration (ex: PT10M4S )
displayMissing() {
    # Desc: Displays missing apps, files, and dirs
    # Usage: displayMissing
    # Input: associative arrays: appRollCall, fileRollCall, dirRollCall
    # Output: stderr messages
    #==BEGIN Display errors==
    #===BEGIN Display Missing Apps===
    missingApps="Missing apps  :"
    #for key in "${!appRollCall[@]}"; do echo "DEBUG:$key => ${appRollCall[$key]}"; done
    for key in "${!appRollCall[@]}"; do
	value="${appRollCall[$key]}"
	if [ "$value" = "false" ]; then
	    #echo "DEBUG:Missing apps: $key => $value";
	    missingApps="$missingApps""$key "
	    appMissing="true"
	fi
    done
    if [ "$appMissing" = "true" ]; then  # Only indicate if an app is missing.
	echo "$missingApps" 1>&2;
    fi
    #===END Display Missing Apps===

    #===BEGIN Display Missing Files===
    missingFiles="Missing files:"
    #for key in "${!fileRollCall[@]}"; do echo "DEBUG:$key => ${fileRollCall[$key]}"; done
    for key in "${!fileRollCall[@]}"; do
	value="${fileRollCall[$key]}"
	if [ "$value" = "false" ]; then
	    #echo "DEBUG:Missing files: $key => $value";
	    missingFiles="$missingFiles""$key "
	    fileMissing="true"
	fi
    done
    if [ "$fileMissing" = "true" ]; then  # Only indicate if an app is missing.
	echo "$missingFiles" 1>&2;
    fi
    #===END Display Missing Files===

    #===BEGIN Display Missing Directories===
    missingDirs="Missing dirs:"
    #for key in "${!dirRollCall[@]}"; do echo "DEBUG:$key => ${dirRollCall[$key]}"; done
    for key in "${!dirRollCall[@]}"; do
	value="${dirRollCall[$key]}"
	if [ "$value" = "false" ]; then
	    #echo "DEBUG:Missing dirs: $key => $value";
	    missingDirs="$missingDirs""$key "
	    dirMissing="true"
	fi
    done
    if [ "$dirMissing" = "true" ]; then  # Only indicate if an dir is missing.
	echo "$missingDirs" 1>&2;
    fi
    #===END Display Missing Directories===

    #==END Display errors==
} # Display missing apps, files, dirs
setScriptTTL() {
    #Desc: Sets script TTL
    #Usage: setScriptTTL arg1
    #Input: arg1: "day" or "hour"
    #Output: scriptTTL
    #Depends: timeUntilNextHour or timeUntilNextDay
    local ARG1
    ARG1="$1"
    if [[ "$ARG1" = "day" ]]; then
	    # Set script lifespan to end at start of next day
	if ! scriptTTL="$(timeUntilNextDay)"; then
	    if [[ "$scriptTTL" -eq 0 ]]; then
	    ((scriptTTL++)); # Add 1 because 0 would cause 'timeout' to never timeout.
	    else
	    yell "ERROR: timeUntilNextDay exit code $?"; exit 1;
	    fi;
	fi;
    elif [[ "$ARG1" = "hour" ]]; then
	# Set script lifespan to end at start of next hour
	if ! scriptTTL="$(timeUntilNextHour)"; then
	    if [[ "$scriptTTL" -eq 0 ]]; then
		((scriptTTL++)); # Add 1 because 0 would cause 'timeout' to never timeout.
	    else
		yell "ERROR: timeUntilNextHour exit code $?"; exit 1;
	    fi;
	fi;
    else
	yell "ERROR:Invalid argument for setScriptTTL function."; exit 1;
    fi
} # Seconds until next (day|hour).
checkMakeTar() {
    # Desc: Checks that a valid tar archive exists, creates one otherwise
    # Usage: checkMakeTar [ path ]
    # Version: 1.0.1
    # Input: arg1: path of tar archive
    # Output: exit code 0 : tar readable
    #         exit code 1 : tar missing; created
    #         exit code 2 : tar not readable; moved; replaced
    # Depends: try, tar, date
    local PATH_TAR returnFlag0 returnFlag1 returnFlag2
    PATH_TAR="$1"

    # Check if file is a valid tar archive
    if tar --list --file="$PATH_TAR" 1>/dev/null 2>&1; then
	## T1: return success
	returnFlag0="tar valid";
    else
	## F1: Check if file exists
	if [[ -f "$PATH_TAR" ]]; then
	    ### T: Rename file
	    try mv "$PATH_TAR" "$PATH_TAR""--broken--""$(date +%Y%m%dT%H%M%S)" && \
		returnFlag1="tar moved";
	else
	    ### F: -
	    :
	fi
	## F2: Create tar archive, return 0
	try tar --create --file="$PATH_TAR" --files-from=/dev/null && \
	    returnFlag2="tar created";
    fi
    
    # Determine function return code
    if [[ "$returnFlag0" = "tar valid" ]]; then
	return 0;
    elif [[ "$returnFlag2" = "tar created" ]] && ! [[ "$returnFlag1" = "tar moved" ]]; then
	return 1; # tar missing so created
    elif [[ "$returnFlag2" = "tar created" ]] && [[ "$returnFlag1" = "tar moved" ]]; then
	return 2; # tar not readable so moved; replaced
    fi
} # checks if arg1 is tar; creates one otherwise
appendArgTar(){
    # Desc: Writes first argument to temporary file with arguments as options, then appends file to tar
    # Usage: appendArgTar "$(echo "Data to be written.")" [name of file to be inserted] [tar path] [temp dir] ([cmd1] [cmd2] [cmd3] [cmd4]...)
    # Version: 1.0.3
    # Input: arg1: data to be written
    #        arg2: file name of file to be inserted into tar
    #        arg3: tar archive path (must exist first)
    #        arg4: temporary working dir
    #        arg5+: command strings (ex: "gpsbabel -i nmea -f - -o kml -F - ")
    # Output: file written to disk
    # Example: decrypt multiple large files in parallel
    #          appendArgTar "$(cat /tmp/largefile1.gpg)" "largefile1" $HOME/archive.tar /tmp "gpg --decrypt" &
    #          appendArgTar "$(cat /tmp/largefile2.gpg)" "largefile2" $HOME/archive.tar /tmp "gpg --decrypt" &
    #          appendArgTar "$(cat /tmp/largefile3.gpg)" "largefile3" $HOME/archive.tar /tmp "gpg --decrypt" &
    # Depends: bash 5
    # Ref/Attrib: Using 'eval' to construct command strings https://askubuntu.com/a/476533

    # Save function name
    local FN="${FUNCNAME[0]}";
    #yell "DEBUG:STATUS:$FN:Finished appendArgTar()."
    
    # Set file name
    if ! [ -z "$2" ]; then FILENAME="$2"; else yell "ERROR:$FN:Not enough arguments."; exit 1; fi
    
    # Check tar path is a file
    if [ -f "$3" ]; then TAR_PATH="$3"; else yell "ERROR:$FN:Tar archive arg not a file."; exit 1; fi
	
    # Check temp dir arg
    if ! [ -z "$4" ]; then TMP_DIR="$4"; else yell "ERROR:$FN:No temporary working dir set."; exit 1; fi
    
    # Set command strings
    if ! [ -z "$5" ]; then CMD1="$5"; else CMD1="tee /dev/null "; fi # command string 1
    if ! [ -z "$6" ]; then CMD2="$6"; else CMD2="tee /dev/null "; fi # command string 2
    if ! [ -z "$7" ]; then CMD3="$7"; else CMD3="tee /dev/null "; fi # command string 3
    if ! [ -z "$8" ]; then CMD4="$8"; else CMD4="tee /dev/null "; fi # command string 4

    # Input command
    CMD0="echo \"\$1\""

    # # Debug
    # yell "DEBUG:STATUS:$FN:CMD0:$CMD0"
    # yell "DEBUG:STATUS:$FN:CMD1:$CMD1"
    # yell "DEBUG:STATUS:$FN:CMD2:$CMD2"
    # yell "DEBUG:STATUS:$FN:CMD3:$CMD3"
    # yell "DEBUG:STATUS:$FN:CMD4:$CMD4"
    # yell "DEBUG:STATUS:$FN:FILENAME:$FILENAME"
    # yell "DEBUG:STATUS:$FN:TAR_PATH:$TAR_PATH"
    # yell "DEBUG:STATUS:$FN:TMP_DIR:$TMP_DIR"
    
    # Write to temporary working dir
    eval "$CMD0"" | ""$CMD1"" | ""$CMD2"" | ""$CMD3"" | ""$CMD4" > "$TMP_DIR"/"$FILENAME";

    # Append to tar
    try tar --append --directory="$TMP_DIR" --file="$TAR_PATH" "$FILENAME";
    #yell "DEBUG:STATUS:$FN:Finished appendArgTar()."
} # Append Bash var to file appended to Tar archive
appendFileTar(){
    # Desc: Processes first file and then appends to tar
    # Usage: appendFileTar [file path] [name of file to be inserted] [tar path] [temp dir] ([cmd1] [cmd2] [cmd3] [cmd4]...)
    # Version: 1.0.2
    # Input: arg1: path of file to be (processed and) written
    #        arg2: name to use for file inserted into tar
    #        arg3: tar archive path (must exist first)
    #        arg4: temporary working dir
    #        arg5+: command strings (ex: "gpsbabel -i nmea -f - -o kml -F - ")
    # Output: file written to disk
    # Example: decrypt multiple large files in parallel
    #          appendFileTar /tmp/largefile1.gpg "largefile1" $HOME/archive.tar /tmp "gpg --decrypt" &
    #          appendFileTar /tmp/largefile2.gpg "largefile2" $HOME/archive.tar /tmp "gpg --decrypt" &
    #          appendFileTar /tmp/largefile3.gpg "largefile3" $HOME/archive.tar /tmp "gpg --decrypt" &
    # Depends: bash 5

    # Save function name
    local FN="${FUNCNAME[0]}";
    #yell "DEBUG:STATUS:$FN:Finished appendFileTar()."
    
    # Set file name
    if ! [ -z "$2" ]; then FILENAME="$2"; else yell "ERROR:$FN:Not enough arguments."; exit 1; fi
    # Check tar path is a file
    if [ -f "$3" ]; then TAR_PATH="$3"; else yell "ERROR:$FN:Tar archive arg not a file."; exit 1; fi
    # Check temp dir arg
    if ! [ -z "$4" ]; then TMP_DIR="$4"; else yell "ERROR:$FN:No temporary working dir set."; exit 1; fi
    # Set command strings
    if ! [ -z "$5" ]; then CMD1="$5"; else CMD1="tee /dev/null "; fi # command string 1
    if ! [ -z "$6" ]; then CMD2="$6"; else CMD2="tee /dev/null "; fi # command string 2
    if ! [ -z "$7" ]; then CMD3="$7"; else CMD3="tee /dev/null "; fi # command string 3
    if ! [ -z "$8" ]; then CMD4="$8"; else CMD4="tee /dev/null "; fi # command string 4

    # Input command string
    CMD0="cat \"\$1\""
    
    # # Debug
    # yell "DEBUG:STATUS:$FN:CMD0:$CMD0"
    # yell "DEBUG:STATUS:$FN:CMD1:$CMD1"
    # yell "DEBUG:STATUS:$FN:CMD2:$CMD2"
    # yell "DEBUG:STATUS:$FN:CMD3:$CMD3"
    # yell "DEBUG:STATUS:$FN:CMD4:$CMD4"
    # yell "DEBUG:STATUS:$FN:FILENAME:$FILENAME"
    # yell "DEBUG:STATUS:$FN:TAR_PATH:$TAR_PATH"
    # yell "DEBUG:STATUS:$FN:TMP_DIR:$TMP_DIR"
    
    # Write to temporary working dir
    eval "$CMD0 | $CMD1 | $CMD2 | $CMD3 | $CMD4" > "$TMP_DIR"/"$FILENAME";

    # Append to tar
    try tar --append --directory="$TMP_DIR" --file="$TAR_PATH" "$FILENAME";
    #yell "DEBUG:STATUS:$FN:Finished appendFileTar()."
} # Append file to Tar archive
checkAgePubkey() {
    # Desc: Checks if string is an age-compatible pubkey
    # Usage: checkAgePubkey [str pubkey]
    # Version: 0.1.2
    # Input: arg1: string
    # Output: return code 0: string is age-compatible pubkey
    #         return code 1: string is NOT an age-compatible pubkey
    #         age stderr (ex: there is stderr if invalid string provided)
    # Depends: age (v0.1.0-beta2; https://github.com/FiloSottile/age/releases/tag/v1.0.0-beta2 )
    
    argPubkey="$1";
    
    if echo "test" | age -a -r "$argPubkey" 1>/dev/null; then
	return 0;
    else
	return 1;
    fi;
} # Check age pubkey
validateInput() {
    # Desc: Validates Input
    # Usage: validateInput [str input] [str input type]
    # Version: 0.2.1
    # Input: arg1: string to validate
    #        arg2: string specifying input type (ex:"ssh_pubkey")
    # Output: return code 0: if input string matched specified string type
    # Depends: bash 5, yell

    # Save function name
    local FN="${FUNCNAME[0]}";

    # Process arguments
    argInput="$1";
    argType="$2";
    if [[ $# -gt 2 ]]; then yell "ERROR:$0:$FN:Too many arguments."; exit 1; fi;

    # Check for blank
    if [[ -z "$argInput" ]]; then return 1; fi
    
    # Define input types
    ## ssh_pubkey
    ### Check for alnum/dash base64 (ex: "ssh-rsa AAAAB3NzaC1yc2EAAA")
    if [[ "$argType" = "ssh_pubkey" ]]; then
	if [[ "$argInput" =~ ^[[:alnum:]-]*[\ ]*[[:alnum:]+/=]*$ ]]; then
	return 0; fi; fi;

    ## age_pubkey
    ### Check for age1[:bech32:]
    if [[ "$argType" = "age_pubkey" ]]; then
	if [[ "$argInput" =~ ^age1[qpzry9x8gf2tvdw0s3jn54khce6mua7l]*$ ]]; then
	    return 0; fi; fi

    # Return error if no condition matched.
    return 1;
} # Validates strings
magicWriteVersion() {
    # Desc: Appends time-stamped VERSION to PATHOUT_TAR
    # Usage: magicWriteVersion
    # Version: 0.1.0
    # Input: CONTENT_VERSION, FILEOUT_VERSION, PATHOUT_TAR, DIR_TMP
    # Input: SCRIPT_VERSION, SCRIPT_URL, AGE_VERSION, AGE_URL, SCRIPT_HOSTNAME
    # Output: appends tar PATHOUT_TAR
    # Depends: dateTimeShort, appendArgTar
    local CONTENT_VERSION pubKeyIndex
    
    # Set VERSION file name
    FILEOUT_VERSION="$(dateTimeShort)..VERSION";

    # Gather VERSION data in CONTENT_VERSION
    CONTENT_VERSION="SCRIPT_VERSION=$SCRIPT_VERSION";
    #CONTENT_VERSION="$CONTENT_VERSION""\\n";
    CONTENT_VERSION="$CONTENT_VERSION""\\n""SCRIPT_NAME=$SCRIPT_NAME";
    CONTENT_VERSION="$CONTENT_VERSION""\\n""SCRIPT_URL=$SCRIPT_URL";
    CONTENT_VERSION="$CONTENT_VERSION""\\n""AGE_VERSION=$AGE_VERSION";
    CONTENT_VERSION="$CONTENT_VERSION""\\n""AGE_URL=$AGE_URL";
    CONTENT_VERSION="$CONTENT_VERSION""\\n""DATE=$(date --iso-8601=seconds)";
    CONTENT_VERSION="$CONTENT_VERSION""\\n""HOSTNAME=$SCRIPT_HOSTNAME";
    ## Add list of recipient pubkeys
    for pubkey in "${recPubKeysValid[@]}"; do
	((pubKeyIndex++))
	CONTENT_VERSION="$CONTENT_VERSION""\\n""PUBKEY_$pubKeyIndex=$pubkey";
    done
    ## Process newline escapes
    CONTENT_VERSION="$(echo -e "$CONTENT_VERSION")"

    # Write CONTENT_VERSION as file FILEOUT_VERSION and write-append to PATHOUT_TAR
    appendArgTar "$CONTENT_VERSION" "$FILEOUT_VERSION" "$PATHOUT_TAR" "$DIR_TMP";
    
} # bkgpslog: write version data to PATHOUT_TAR via appendArgTar()
magicGatherWriteBuffer() {
    # Desc: bkgpslog-specific meta function for writing data to DIR_TMP then appending each file to PATHOUT_TAR
    # Inputs: PATHOUT_TAR FILEOUT_{NMEA,GPX,KML} CMD_CONV_{NMEA,GPX,KML} CMD_{COMPRESS,ENCRYPT} DIR_TMP,
    # Inputs: BUFFER_TTL bufferTTL_STR SCRIPT_HOSTNAME CMD_COMPRESS_SUFFIX CMD_ENCRYPT_SUFFIX
    # Depends: yell, try, vbm, appendArgTar, tar
    local FN="${FUNCNAME[0]}";
    wait; # Wait to avoid collision with older magicWriteBuffer() instances (see https://www.tldp.org/LDP/abs/html/x9644.html )
    # Create buffer file with unique name
    PATHOUT_BUFFER="$DIR_TMP/buffer$SECONDS";
    # Fill buffer
    timeout "$BUFFER_TTL"s gpspipe -r -o "$PATHOUT_BUFFER" ;
    timeBufferStart="$(dateTimeShort  "$(date --date="$BUFFER_TTL seconds ago")")"; # Note start time
    vbm "DEBUG:STATUS:$FN:Started magicWriteBuffer().";
    # Determine file paths (time is start of buffer period)
    FILEOUT_BASENAME="$timeBufferStart""--""$bufferTTL_STR""..""$SCRIPT_HOSTNAME""_location" && vbm "STATUS:Set FILEOUT_BASENAME to:$FILEOUT_BASENAME";
    ## Files saved to DIR_TMP
    FILEOUT_NMEA="$FILEOUT_BASENAME".nmea"$CMD_COMPRESS_SUFFIX""$CMD_ENCRYPT_SUFFIX" && vbm "STATUS:Set FILEOUT_NMEA to:$FILEOUT_NMEA";
    FILEOUT_GPX="$FILEOUT_BASENAME".gpx"$CMD_COMPRESS_SUFFIX""$CMD_ENCRYPT_SUFFIX" && vbm "STATUS:Set FILEOUT_GPX to:$FILEOUT_GPX";
    FILEOUT_KML="$FILEOUT_BASENAME".kml"$CMD_COMPRESS_SUFFIX""$CMD_ENCRYPT_SUFFIX" && vbm "STATUS:Set FILEOUT_KML to:$FILEOUT_KML";
    PATHOUT_NMEA="$DIR_TMP"/"$FILEOUT_NMEA" && vbm "STATUS:Set PATHOUT_NMEA to:$PATHOUT_NMEA";
    PATHOUT_GPX="$DIR_TMP"/"$FILEOUT_GPX" && vbm "STATUS:Set PATHOUT_GPX to:$PATHOUT_GPX";
    PATHOUT_KML="$DIR_TMP"/"$FILEOUT_KML" && vbm "STATUS:Set PATHOUT_KML to:$PATHOUT_KML";
    ## Files saved to disk (DIR_OUT)
    ### one file per day (Ex: "20200731..hostname_location.[.gpx.gz].tar")
    PATHOUT_TAR="$DIR_OUT"/"$(dateShort "$(date --date="$BUFFER_TTL seconds ago")")".."$SCRIPT_HOSTNAME""_location""$CMD_COMPRESS_SUFFIX""$CMD_ENCRYPT_SUFFIX".tar && \
	vbm "STATUS:Set PATHOUT_TAR to:$PATHOUT_TAR";
    # DEBUG: check vars
    vbm "STATUS:DIR_TMP     :$DIR_TMP";
    vbm "STATUS:PATHOUT_TAR :$PATHOUT_TAR";
    vbm "STATUS:PATHOUT_NMEA:$PATHOUT_NMEA";
    vbm "STATUS:PATHOUT_GPX:$PATHOUT_GPX";
    vbm "STATUS:PATHOUT_KML:$PATHOUT_KML";
    
    
    # Validate PATHOUT_TAR as tar.
    checkMakeTar "$PATHOUT_TAR";
    ## Add VERSION file if checkMakeTar had to create a tar (exited 1) or replace one (exited 2)
    if [[ $? -eq 1 ]] || [[ $? -eq 2 ]]; then magicWriteVersion; fi

    # Write bufferBash to PATHOUT_TAR
    appendFileTar "$PATHOUT_BUFFER" "$FILEOUT_NMEA" "$PATHOUT_TAR" "$DIR_TMP" "$CMD_CONV_NMEA" "$CMD_COMPRESS" "$CMD_ENCRYPT"; # Write NMEA data
    appendFileTar "$PATHOUT_BUFFER" "$FILEOUT_GPX" "$PATHOUT_TAR" "$DIR_TMP" "$CMD_CONV_GPX" "$CMD_COMPRESS" "$CMD_ENCRYPT"; # Write GPX file
    appendFileTar "$PATHOUT_BUFFER" "$FILEOUT_KML" "$PATHOUT_TAR" "$DIR_TMP" "$CMD_CONV_KML" "$CMD_COMPRESS" "$CMD_ENCRYPT"; # Write KML file

    # Remove secured chunks from DIR_TMP
    rm "$PATHOUT_BUFFER" "$PATHOUT_NMEA" "$PATHOUT_GPX" "$PATHOUT_KML";
    vbm "DEBUG:STATUS:$FN:Finished magicWriteBuffer().";
} # write buffer to disk
magicParseRecipientDir() {
    # Desc: Updates recPubKeysValid with pubkeys in dir specified by '-R' option ("recipient directory")
    # Inputs: vars: OPTION_RECDIR, argRecDir, 
    #         arry: recPubKeysValid
    # Outputs: arry: recPubKeysValid (modified with pubkeys in argRecDir if pubkeys valid)
    # Depends: processArguments,
    local recFileLine updateRecipients recipientDir
    declare -a candRecPubKeysValid
    
    if [[ "$OPTION_RECDIR" = "true" ]]; then
	### Check that argRecDir is a directory.
	if [[ -d "$argRecDir" ]]; then
	    recipientDir="$argRecDir";
	    #### Initialize variable indicating outcome of pubkey review
	    unset updateRecipients
	    #### Add existing recipients
	    candRecPubKeysValid=(${recPubKeysValid[@]});
	    #### Parse files in recipientDir
	    for file in "$recipientDir"/*; do
		##### Read first line of each file
		recFileLine="$(cat "$file" | head -n1)";
		##### check if first line is a valid pubkey
		if checkAgePubkey "$recFileLine" && \
			( validateInput "$recFileLine" "ssh_pubkey" || validateInput "$recFileLine" "age_pubkey"); then
		    ###### T: add candidate pubkey to candRecPubKeysValid
		    candRecPubKeysValid+=("$recFileLine");
		else
		    ###### F: throw warning;
		    yell "ERROR:Invalid recipient file detected. Not modifying recipient list."
		    updateRecipients="false";
		fi;
	    done
	    #### Write updated recPubKeysValid array to recPubKeysValid if no failure detected
	    if ! updateRecipients="false"; then
		recPubKeysValid=(${candRecPubKeysValid[@]});
	    fi;
	else
	    yell "ERROR:$0:Recipient directory $argRecDir does not exist. Exiting."; exit 1;
	fi;
    fi;
} # Update recPubKeysValid with argRecDir
magicParseRecipientArgs() {
    # Desc: Parses recipient arguments specified by '-r' option
    # Input:  vars: OPTION_ENCRYPT from processArguments()
    #         arry: argRecPubKeys from processArguments()
    # Output: vars: CMD_ENCRYPT, CMD_ENCRYPT_SUFFIX
    #         arry: recPubKeysValid
    # Depends: checkapp(), checkAgePubkey(), validateInput(), processArguments()
    local recipients

    # Check if encryption option active.
    if [[ "$OPTION_ENCRYPT" = "true" ]] && [[ "$OPTION_RECIPIENTS" = "true" ]]; then 
	if checkapp age; then # Check that age is available.
	    for pubkey in "${argRecPubKeys[@]}"; do # Validate recipient pubkey strings by forming test message
		vbm "DEBUG:Testing pubkey string:$pubkey";
		if checkAgePubkey "$pubkey" && \
			( validateInput "$pubkey" "ssh_pubkey" || validateInput "$pubkey" "age_pubkey"); then
		    #### Form age recipient string
		    recipients="$recipients""-r '$pubkey' ";
		    vbm "STATUS:Added pubkey for forming age recipient string:""$pubkey";
		    vbm "DEBUG:recipients:""$recipients";
		    #### Add validated pubkey to recPubKeysValid array
		    recPubKeysValid+=("$pubkey") && vbm "DEBUG:recPubkeysValid:pubkey added:$pubkey";
		else
		    yell "ERROR:Exit code ""$?"". Invalid recipient pubkey string. Exiting."; exit 1;
		fi;
	    done
	    vbm "DEBUG:Finished processing argRecPubKeys array";

	    ##  Form age command string
	    CMD_ENCRYPT="age ""$recipients " && vbm "CMD_ENCRYPT:$CMD_ENCRYPT";
	    CMD_ENCRYPT_SUFFIX=".age" && vbm "CMD_ENCRYPT_SUFFIX:$CMD_ENCRYPT_SUFFIX";
	else
	    yell "ERROR:Encryption enabled but \"age\" not found. Exiting."; exit 1;
	fi;
    else
	CMD_ENCRYPT="tee /dev/null " && vbm "CMD_ENCRYPT:$CMD_ENCRYPT";
	CMD_ENCRYPT_SUFFIX="" && vbm "CMD_ENCRYPT_SUFFIX:$CMD_ENCRYPT_SUFFIX";
	vbm "DEBUG:Encryption not enabled."
    fi;
    # Catch case if '-e' is set but '-r' or '-R' is not
    if [[ "$OPTION_ENCRYPT" = "true" ]] && [[ ! "$OPTION_RECIPIENTS" = "true" ]]; then
	yell "ERROR:\'-e\' set but no \'-r\' or \'-R\' set."; exit 1; fi;
    # Catch case if '-r' or '-R' set but '-e' is not
    if [[ ! "$OPTION_ENCRYPT" = "true" ]] && [[ "$OPTION_RECIPIENTS" = "true" ]]; then
	yell "ERROR:\'-r\' or \'-R\' set but \'-e\' is not set."; exit 1; fi; 
} # Populate recPubKeysValid with argRecPubKeys; form encryption cmd string and filename suffix
magicParseCompressionArg() {
    # Desc: Parses compression arguments specified by '-c' option
    # Input:  vars: OPTION_COMPRESS
    # Output: CMD_COMPRESS, CMD_COMPRESS_SUFFIX
    # Depends: checkapp(), vbm(), gzip, 
    if [[ "$OPTION_COMPRESS" = "true" ]]; then # Check if compression option active
	if checkapp gzip; then # Check if gzip available
	    CMD_COMPRESS="gzip " && vbm "CMD_COMPRESS:$CMD_COMPRESS";
	    CMD_COMPRESS_SUFFIX=".gz" && vbm "CMD_COMPRESS_SUFFIX:$CMD_COMPRESS_SUFFIX";
	else
	    yell "ERROR:Compression enabled but \"gzip\" not found. Exiting."; exit 1;
	fi
    else
	CMD_COMPRESS="tee /dev/null " && vbm "CMD_COMPRESS:$CMD_COMPRESS";
	CMD_COMPRESS_SUFFIX="" && vbm "CMD_COMPRESS_SUFFIX:$CMD_COMPRESS_SUFFIX";
	vbm "DEBUG:Compression not enabled.";
    fi    
} # Form compression cmd string and filename suffix
magicInitWorkingDir() {
    # Desc: Determine temporary working directory from defaults or user input
    # Input:  vars: OPTION_TEMPDIR, argTmpDirPriority, DIR_TMP_DEFAULT
    # Input:  vars: SCRIPT_TIME_START
    # Output: vars: DIR_TMP
    # Depends: processArguments(), vbm(), yell()
    # Parse '-t' option (user-specified temporary working dir)
    ## Set DIR_TMP_PARENT to user-specified value if specified
    local DIR_TMP_PARENT
    
    if [[ "$OPTION_TMPDIR" = "true" ]]; then
	if [[ -d "$argTempDirPriority" ]]; then
	    DIR_TMP_PARENT="$argTempDirPriority"; 
	else
	    yell "WARNING:Specified temporary working directory not valid:$OPTION_TMPDIR";
	    exit 1; # Exit since user requires a specific temp dir and it is not available.
	fi;
    else
    ## Set DIR_TMP_PARENT to default or fallback otherwise
	if [[ -d "$DIR_TMP_DEFAULT" ]]; then
	    DIR_TMP_PARENT="$DIR_TMP_DEFAULT";
	elif [[ -d /tmp ]]; then
	    yell "WARNING:$DIR_TMP_DEFAULT not available. Falling back to /tmp .";
	    DIR_TMP_PARENT="/tmp";
	else
	    yell "ERROR:No valid working directory available. Exiting.";
	    exit 1;
	fi
    fi;
    ## Set DIR_TMP using DIR_TMP_PARENT and nonce (SCRIPT_TIME_START)
    DIR_TMP="$DIR_TMP_PARENT"/"$SCRIPT_TIME_START""..bkgpslog" && vbm "DEBUG:Set DIR_TMP to:$DIR_TMP"; # Note: removed at end of main().    
} # Sets working dir

main() {
    # Process arguments
    processArguments "$@";
    ## Act upon arguments
    ### Determine working directory
    magicInitWorkingDir;
    ### Set output encryption and compression option strings
    #### React to "-r" ("encryption recipients") option
    magicParseRecipientArgs;
    #### React to "-c" ("compression") option
    magicParseCompressionArg;
    #### React to "-R" ("recipient directory") option
    magicParseRecipientDir;

    # Check that critical apps and dirs are available, display missing ones.
    if ! checkapp gpspipe tar && ! checkdir "$DIR_OUT" "DIR_TMP"; then
	yell "ERROR:Critical components missing.";
	displayMissing; yell "Exiting."; exit 1; fi

    # Set script lifespan
    setScriptTTL "$SCRIPT_TTL"; # seconds until next new SCRIPT_TTL (ex: "day" or "hour")

    # File name substring: encoded bufferTTL
    bufferTTL_STR="$(timeDuration $BUFFER_TTL)";

    # Init temp working dir
    try mkdir "$DIR_TMP" && vbm "DEBUG:Working dir creatd at:$DIR_TMP";

    # Initialize 'tar' archive
    ## Define output tar path (note: each day gets *one* tar file (Ex: "20200731..hostname_location.[.gpx.gz].tar"))
    PATHOUT_TAR="$DIR_OUT"/"$(dateShort)".."$SCRIPT_HOSTNAME""_location""$CMD_COMPRESS_SUFFIX""$CMD_ENCRYPT_SUFFIX".tar && \
	vbm "STATUS:Set PATHOUT_TAR to:$PATHOUT_TAR";
    ## Check that PATHOUT_TAR is a tar. Rename old and create empty one otherwise.
    checkMakeTar "$PATHOUT_TAR" && vbm "DEBUG:Confirmed or Created to be a tar:$PATHOUT_TAR";
    ## Append VERSION file to PATHOUT_TAR
    magicWriteVersion;

    # Define GPS conversion commands
    CMD_CONV_NMEA="tee /dev/null " && vbm "STATUS:Set CMD_CONV_NMEA to:$CMD_CONV_NMEA"; # tee as passthrough
    CMD_CONV_GPX="gpsbabel -i nmea -f - -o gpx -F - " && vbm "STATUS:Set CMD_CONV_GPX to:$CMD_CONV_GPX"; # convert NMEA to GPX
    CMD_CONV_KML="gpsbabel -i nmea -f - -o kml -F - " && vbm "STATUS:Set CMD_CONV_KML to:$CMD_CONV_KML"; # convert NMEA to KML

    # MAIN LOOP:Record gps data until script lifespan ends
    while [[ "$SECONDS" -lt "$scriptTTL" ]]; do
	magicGatherWriteBuffer &
	sleep "$BUFFER_TTL";
    done    

    # Cleanup
    ## Remove DIR_TMP
    try rm -r "$DIR_TMP";

    vbm "STATUS:Main function finished.";
} # Main function.
#===END Declare local script functions===
#==END Define script parameters==


#==BEGIN Perform work and exit==
main "$@" # Run main function.
exit 0;
#==END Perform work and exit==