c shell script help with find

Okie here is my problem,

  1. I have a directory with a ton of files.
  2. I want to first get an input on how many days ago the files were created.
  3. I will take those files and put it into another file
  4. Then I will take the last # from each line and subtract by 1 then diff the line from the file from the line that was subtracted.

I was thinking of first using
ex: "find . -name '*file_num_*' -print > latestfiles"
then i am unsure of where to go from there.

is there a flag on find that will let me take the files created within a date range of certain number of days ago?

okie heres what i got so far in ksh

  1. asks for number of days file was created...
  2. "read day_ago"
  3. "find . -name '*file_num_*' -mtime -$days_ago -print > File"

Now i just need to know how to subtract the last 2 characters from each line on the file by 1

then diff the original with the subtracted version.