List of last generated file on each day from 7 days list - shell

Question

I've a list of files in the following format:
Group_2012_01_06_041505.csv
Region_2012_01_06_041508.csv
Region_2012_01_06_070007.csv
XXXX_YYYY_MM_DD_HHMMSS.csv
What is the best way to compile a list of last generated file for each day per group from last 7 days list?
Version that worked on HP-UX
for d in 6 5 4 3 2 1 0
do
DATES[d]=$(perl -e "use POSIX;print strftime '%Y_%m_%d%',localtime time-86400*$d;")
done
for group in `ls *.csv | cut -d_ -f1 | sort -u`
do
CSV_FILES=$working_dir/*.csv
if [ ! -f $CSV_FILES ]; then
break # if no file exists do not attempt processing
fi
for d in "${DATES[#]}"
do
file_nm=$(ls ${group}_$d* 2>>/dev/null | sort -r | head -1)
if [ "$file_nm" != "" ]
then
# Process file
fi
done
done

Answer 1

You can explicitly iterate over the group/time combinations:
for d in {1..6}
do
DATES[d]=`gdate +"%Y_%m_%d" -d "$d day ago"`
done
for group in `ls *csv | cut -d_ -f1 | sort -u`
do
for d in "${DATES[#]}"
do
echo "$group $d: " `ls ${group}_$d* 2>>/dev/null | sort -r | head -1`
done
done
Which outputs the following for your example data set:
Group 2012_01_06: Group_2012_01_06_041505.csv
Group 2012_01_05:
Group 2012_01_04:
Group 2012_01_03:
Group 2012_01_02:
Group 2012_01_01:
Region 2012_01_06: Region_2012_01_06_070007.csv
Region 2012_01_05:
Region 2012_01_04:
Region 2012_01_03:
Region 2012_01_02:
Region 2012_01_01:
XXXX 2012_01_06:
XXXX 2012_01_05:
XXXX 2012_01_04:
XXXX 2012_01_03:
XXXX 2012_01_02:
XXXX 2012_01_01:
Note Region_2012_01_06_041508.csv is not shown for Region 2012_01_06 as it is older than Region_2012_01_06_070007.csv