fix-bogus-dates

#!/bin/bash
# Copyright 2014 Edward J Huff ejhuff at gmail.com, not a work for hire.
# License: any GPL or BSD or MIT or any free software license.

# bash script to fix bogus weekdays in rpm spec files.

# This script automatically corrects bogus weekdays in spec files, generating a
# changelog entry and adding a line after the bogus date noting the original date.
# (The weekday might have been correct and the day of the month wrong).
# The input file is copied to a backup file, and a diff is printed.

[[ $# > 0 ]] || { echo "Usage: $0 packagename.spec ..."; exit 1; }
Www='[A-Z][a-z][a-z]'
Mmm='[A-Z][a-z][a-z]'
DD='[0-9][0-9]'
YYYY='[12][90][0-9][0-9]'
WwwMmmDDYYYY="\($Www\) \($Mmm\) \($DD\) \($YYYY\)"

while [[ $# > 0 ]]; do
    [[ -f "$1" ]] || { echo "$0: $1: no such file."; exit 1; }
    changelog=$(mktemp --tmpdir=. changelog-XXXXXXXXX.txt)
    sedscript=$(mktemp --tmpdir=. sedscript-XXXXXXXXX.sed)
    printf "%s\n" \
	"* $(date +'%a %b %d %Y') BogusDateBot" \
	'- Eliminated rpmbuild "bogus date" warnings due to inconsistent weekday,' \
	"  by assuming the date is correct and changing the weekday." \
	> "$changelog"
    cat "$1" | \
	grep "^\* $Www $Mmm $DD $YYYY" | \
	grep -v '^echo' | \
	sed 's/^\* '"$WwwMmmDDYYYY"'.*$/echo "$(date --date="\2 \3 \4" +"%a \1 %b %d %Y")"/' | \
	grep '^echo' | \
	bash | \
	egrep -v "Mon Mon|Tue Tue|Wed Wed|Thu Thu|Fri Fri|Sat Sat|Sun Sun" | \
	sort -u --key=5,5n --key=3,3M --key=4,4n | \
	while read correct wrong Month Day Year; do
            date="$Month $Day $Year"
            alternatives="$wrong $Month $Day $Year --> "$(
		for ((i = -6; i < 7; i++ )); do
		    date --date "$date $i day" +"%a %b %d %Y or ";
		done | egrep "$date|$wrong" | tr -d \\n;
		printf "%s" "....")
	    printf "  %s\n" "$alternatives" >> "$changelog"
            re='^\* '"$wrong $Month $Day $Year"'\(.*\)$'
            subs='* '"$correct $Month $Day $Year"'\1\n  '"$alternatives"
            printf "%s\n" "s:$re:$subs:" >> "$sedscript"
        done
    printf "\n" >> "$changelog"
    backup="$1"-$(date --utc --ref="$1" +"%Y-%m-%d-%H-%M-%S-%NZ")
    cp -vpf "$1" "$backup"
    cat "$backup" | sed -f "$sedscript" -e '/^%changelog *$/ r '"$changelog" > "$1"
    rm -f "$changelog" "$sedscript"
    diff -u "$backup" "$1"
    shift
done