feat(user/bkphotorights):Run command array with error reporting

[BK-2020-03.git] / unitproc / bkdstcountdown

diff --git a/unitproc/bkdstcountdown b/unitproc/bkdstcountdown
index ee3b094ee236594d575930beca807a4360ba59fd..17ff7fa75a741824c0d139a21ac68ed5e2a582dc 100755 (executable)
--- a/unitproc/bkdstcountdown
+++ b/unitproc/bkdstcountdown
@@ -1,59 +1,64 @@
-#!/bin/bash
-
-# Date: 2020-02-13T23:14Z; baltakatei>
-
-# Description: This script outputs days until the next time zone
-# discontinuity using 'zdump' and 'date'.
-
-#=================ADJUST ME=======================
-SCRIPT_TZ="America/Los_Angeles" # Timezone to check for discontinuities
-#=================================================
-
-echoerr() {
-    echo "$@" 1>&2;
-}
-
-# Declare variables
-declare -a datesDiscontArray #array
-
-SCRIPT_YEAR=$(date +%Y)
-SCRIPT_YEAR_NEXT=$(( $(date +%Y) + 1))
-SCRIPT_RUN_DATE_SECONDS=$(date +%s)
-
-# Save zdump output for SCRIPT_YEAR (for how multiline data saved in variable, see https://stackoverflow.com/a/613580 )
-datesDiscont="$(zdump -c $SCRIPT_YEAR_NEXT -v $SCRIPT_TZ | grep $SCRIPT_YEAR |  awk '{ print $2 " " $3 " " $4 " " $5 " " $6 " " $7 }'; echo)"
-if [ -z "$datesDiscont" ]; then
-    echo "No time discontinuity this year."
-    exit 1
-fi
-
-###echoerr "datesDiscont:--""$datesDiscont""--"
-
-# Count lines in datesDiscont (for counting lines in a variable, see https://stackoverflow.com/a/6314682 )
-#datesDiscontLineCount=$(echo "$datesDiscont" | wc -l)
-
-# Convert datesDiscont into array (for how to process each line in a multiline variable, see https://superuser.com/a/284226 )
-while IFS= read -r line; do
-    #echo "$line"
-    #datesDiscontArray+="$line"
-    datesDiscontArray+=($(date --date="$line" +%s))
-    #echo ${datesDiscontArray[-1]}
-done <<< "$datesDiscont"
-#echoerr ${datesDiscontArray[@]}
-
-# Sort datesDiscontArray (see https://stackoverflow.com/a/11789688 )
-IFS=$'\n' datesDiscontArray=($(sort <<<"${datesDiscontArray[*]}"))
-unset IFS
-
-# Get earliest date in datesDiscontArray that isn't in the past.
-for discontinuityDate in "${datesDiscontArray[@]}"; do
-    ###echoerr "Discontinuity date (seconds):"$discontinuityDate
-    ###echoerr "SCRIPT_RUN_DATE_SECONDS     :"$SCRIPT_RUN_DATE_SECONDS
-    if [ $discontinuityDate -gt $SCRIPT_RUN_DATE_SECONDS ]; then
-       ###echoerr "DEBUG:Date in future."
-       nextDiscontDate="$discontinuityDate"
-       break
-    fi
-done
-
-echo $(( ( $nextDiscontDate - $SCRIPT_RUN_DATE_SECONDS )/86400 ))" days" # Days until next discontinuity date
+#!/usr/bin/env bash
+# Description: Outputs days until next timezone discontinuity
+# Depends: GNU Coreutils 8.32 (date), zdump 2.35, Bash 5.1.16
+#   BK-2020-03: yell(), die(), must()
+# Version: 0.1.0
+
+# User config
+script_tz="America/Los_Angeles"; # Timezone to check for discontinuities
+
+yell() { echo "$0: $*" >&2; } # Yell, Die, Try Three-Fingered Claw technique; # Ref/Attrib: https://stackoverflow.com/a/25515370
+die() { yell "$*"; exit 111; }
+must() { "$@" || die "cannot $*"; }
+main() {
+    declare -a datesDiscontArray; #array
+
+    # plumbing
+    script_year="$(date +%Y)";
+    script_year_next="$(( script_year + 1 ))";
+    script_year_next2="$(( script_year + 2 ))";
+    script_run_date_seconds="$(date +%s)";
+
+    # Get discontinuity dates from zdump (see https://stackoverflow.com/a/613580 )
+    datesDiscont="$(zdump -c "$script_year","$script_year_next2" -v $script_tz | \
+      grep "$script_year\|$script_year_next" | \
+      awk '{ print $2 " " $3 " " $4 " " $5 " " $6 " " $7 }'; echo)"; # get dates
+    if [[ -z "$datesDiscont" ]]; then
+        yell "STATUS:No time discontinuity this year.";
+        exit 1;
+    fi;
+
+    # Convert datesDiscont into array
+    while read -r line; do
+        tunix="$(date --date="$line" +%s)"; # get unix epoch seconds
+        datesDiscontArray+=("$tunix");
+    done < <(printf "%s\n" "$datesDiscont");
+
+    # Sort datesDiscontArray
+    while read -r line; do
+        datesDiscontArray+=("$line");
+    done < <(printf "%s\n" "${datesDiscontArray[@]}" | sort);
+
+    # # Get earliest date in datesDiscontArray that isn't in the past.
+    for discontinuityDate in "${datesDiscontArray[@]}"; do
+        if [[ $discontinuityDate -gt $script_run_date_seconds ]]; then
+            nextDiscontDate="$discontinuityDate";
+            break;
+        fi;
+    done;
+
+    # Check that nextDiscontDate is not empty
+    if [[ -z "$nextDiscontDate" ]]; then
+        die "FATAL:nextDiscontDate empty";
+    fi;
+
+    # Calculate days until next discontinuity date
+    output="$(( ( nextDiscontDate - script_run_date_seconds )/86400 )) days";
+    printf "%s\n" "$output";
+
+}; # main program
+
+main "$@";
+
+# Author: Steven Baltakatei Sandoval
+# License: GPLv3+