Question

In short, I want something works like this:

1. When I input a date like 2012-12-27 and want to expand the date by
   week(start with Monday), it
   outputs:2012-12-24,2012-12-25,2012-12-26,2012-12-27,2012-12-28,2012-12-29,2012-12-30
2. When I input a date like 2012-12-27 and want to expand the date by month, it outputs:2012-12-01,2012-12-02 ... 2012-12-31

or, how can I group a bunch of dates by week? e.g. when I input2012-12-01,2012-12-02 ... 2012-12-31. It outputs:2012-12-01,2012-12-02|2012-12-03 ... 2012-12-09|2012-12-10 ... 2012-12-16|...|2012-12-31

I have no idea how to complete this, any clue may be helpful!

Answer 1

DAYSECS=86400                          # seconds in a day
WEEKSECS=604800

echo "Expand on week:"

g_epoch=$(date +"%s" -d $1)            # given date as seconds from epoch
g_dayno=$(date +"%u" -d $1)            # given date as day of week
g_month=$(date +"%m" -d $1)            # given month
g_year=$(date +"%Y" -d $1)             # given year

s_epoch=$(($g_epoch - $DAYSECS * ($g_dayno - 1)))
e_epoch=$(($s_epoch + $WEEKSECS))
for etime in $(seq $s_epoch $DAYSECS $e_epoch); do
  date +"%Y-%m-%d" -d "@$etime"
done

echo "Expand on month:"

s_epoch=$(date +"%s" -d "$g_year-$g_month-01")
e_epoch=$(($s_epoch + 4 * $WEEKSECS))
for etime in $(seq $s_epoch $DAYSECS $e_epoch); do
  if [ $(date +"%m" -d "@$etime") -ne "$g_month" ]; then
    break;
  fi  
  date +"%Y-%m-%d" -d "@$etime"
done