Create 1 file with all movement records in:
msslml:shutter mcrw$ awk -f tidy.awk shutter_20061020_20071011.txt > intermediate/total.txt
msslml:shutter mcrw$ awk -f tidy.awk shutter_20071011_20080802.txt >> intermediate/total.txt
msslml:shutter mcrw$ awk -f tidy.awk shutter.txt >> intermediate/total.txt

Sort the file and remove duplicates:
msslml:shutter mcrw$ cd intermediate
msslml:intermediate mcrw$ sort total.txt > sorted.txt
msslml:intermediate mcrw$ uniq sorted.txt > uniq.txt

Create a file with movement number by day (creates file daily_count.txt):
msslml:intermediate mcrw$ ./by_day.sh 

Filter out blank and impossible dates:
msslml:intermediate mcrw$ awk -f filter_total.awk daily_count.txt > proper_daily_count.txt

Next 2 numbers (4448668) agree. This is the total shutter movements since launch:
msslml:intermediate mcrw$ awk -f filter_total.awk proper_daily_count.txt | awk '{tot+=$3} END {print tot}'
msslml:intermediate mcrw$  awk '{tot+=$3} END {print tot}' uniq.txt 

proper_daily_count.txt contains the number of movements per day where the record exists.